Transition-metal complexes of isatin-beta-thiosemicarbazone. X-ray crystal structure of two nickel 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.

Anticancer Compounds Based on Isatin-Derivatives: Strategies to Ameliorate Selectivity and Efficiency

In this review we compare and discuss results of compounds already reported as anticancer agents based on isatin-derivatives, metalated as well as non-metallated. Isatin compounds can be obtained from plants, marine animals, and is also found in human fluids as a metabolite of amino acids. Its derivatives include imines, hydrazones, thiosemicarbazones, among others, already focused on numerous anticancer studies. Some of them have entered in pre-clinical and clinical tests as antiangiogenic compounds or inhibitors of crucial proteins. As free ligands or coordinated to metal ions, such isatin derivatives showed promising antiproliferative properties against different cancer cells, targeting different biomolecules or organelles. Binding to metal ions usually improves its biological properties, indicating a modulation by the metal and by the ligand in a synergistic process. They also reveal diverse mechanisms of action, being able of binding DNA, generating reactive species that cause oxidative damage, and inhibiting selected proteins. Strategies used to improve the efficiency and selectivity of these compounds comprise structural modification of the ligands, metalation with different ions, syntheses of mononuclear and dinuclear species, and use of inserted or anchored compounds in selected drug delivery systems.

Nickel(II) bis(isatin thiosemicarbazone) complexes induced apoptosis through mitochondrial signaling pathway and G0/G1 cell cycle arrest in IM-9 cells

Three novel complexes (1, 3 and 4) ligating N-substituted isatin thiosemicarbazone derivatives have been synthesized and their structural and biological characteristics have been compared with those of the known analogs (2, 5-7 and 8). In addition, the structure of the representative ligands (L1, L3 and L4) and complex (4) was confirmed by single crystal X-ray diffraction method. All the complexes (1-8) were assessed for their cytotoxic property against a panel of four human cancer cells such as HepG-2 (liver), MOLM-14 (acute monocytic leukemia), U937 (histiocytic lymphoma). and IM-9 (myeloma). Complex 4 exhibited prominent cytotoxic property against MOLM-14, U937 and IM-9 cell lines. Moreover, the results were compared with the well-known anticancer drugs like doxorubicin, cisplatin and daunorubicin. Besides, complex 4 enhanced the apoptotic cell death in IM-9 cell line and induced cell cycle arrest at G1 phase. Western blot analysis revealed the down-regulation of Bcl-2 (b-cell lymphoma-2), up-regulation of Bax (bcl-2 associated X protein), release of cytochrome c and activation of caspases-3 in IM-9 cells by complex 4. Importantly, complex 4 was not toxic to the normal Vero cell line (IC₅₀ > 300 μM). In addition, complex 4 showed the concentration dependent cleavage of supercoiled (SC) DNA to its nicked circular (NC) form.

Comparative studies, synthesis, spectroscopic and characterization of N-methylisatin-3-Girard's T and P hydrazone complexes

Different types of complexes derived from the reactions of N-methylisatin Girard's T hydrazone, N,N,N-trimethyl-2-[(2z)-2-(1-methyl-2-oxo-1,2-dihydro-3H-indole-3-ylidene) hydrazino]-2-oxo-ethan ammonium chloride (MIGT) and N-methylisatin Girard's P hydrazone, 1-{2-(2z)-2-[(1-methyl-2-oxo-1,2-dihydro-3H-indole-3-ylidene) hydrazino]-2-oxoethyl}pyridinium chloride (MIGP) with Fe(3+), Al(3+), Sb(3+) and Sn(2+) salts were synthesized. The isolated complexes were characterized by elemental analyses, molar conductivities, spectral (IR, UV-Vis., (1)H NMR, mass), magnetic moments and thermal measurements. The values of conductance suggest that the complexes are conducting in polar solvents (EtOH, H2O and DMF). The IR spectra suggest that the ligands coordinate in a bidentate and/or tridentate manner via the carbonyl groups of both N-methylisatin and Girard's T and/or P and the (CN) group. The solvents inside and outside the coordination sphere were determined by weight loss and TGA methods. The octahedral geometry of the complexes is confirmed using spectral, magnetic and DFT method from DMOL(3) calculations. The ligands and their metal complexes were tested against different strains of bacteria and fungi.

Synthesis, characterization and modeling structures of isatin-3-Girard T (IGT) and P (IGP) hydrazone complexes

The reactions of isatin Girard's T hydrazone, N,N,N-trimethyl-2-oxo-2[(2z)-2-(2-oxo-1,2-dihydro-3H-indole-3-ylidene)hydrazino]ethan ammonium chloride (IGT) and isatin Girard's P hydrazone, 1-{2-oxo-2-[(2z)(2-oxo-1,2-dihydro-3H-indole-3-ylidene)hydrazine]ethyl} pyridinium chloride (IGP), with Fe(3+), Al(3+), Sb(3+) and Sn(2+) salts afford different types of complexes. The isolated solid complexes were characterized by elemental analyses, molar conductance, spectral (IR, UV-Vis, (1)H NMR, mass), magnetic moment and thermal measurements. The results suggest that all the complexes are conducting in polar solvents (EtOH, H2O and DMF). The IR spectral data suggest that the ligands coordinate in a tridentate manner via the two carbonyl of both isatin and Girard's and the azomethine (C=N) groups. The amounts of solvents inside and outside the coordination sphere were determined using thermal data (TGA) and weight loss method. The octahedral geometry of the complexes is confirmed using DFT method from DMOL(3) calculations. The ligands and their metal complexes were tested against different strains of bacteria and fungi.

Targeting triple negative breast cancer cells by N3-substituted 9,10-phenanthrenequinone thiosemicarbazones and their metal complexes

Novel N(3)-substituted 9,10-Phenanthrenequinone thiosemicarbazones and their copper, nickel and palladium complexes are structurally characterized and reported along with the single crystal X-ray structures of three ligands and one nickel complex. All compounds were evaluated for their antiproliferative potential against Triple Negative Breast Cancer (TNBC) cells which have poor prognosis and no effective drugs to treat with. All compounds exhibited antiproliferative activity against these cells. Among the metal complexes evaluated, redox active copper complexes were found to be more potent. The possible mechanism for such enhanced activity can be attributed to the generation of oxidative stress, which was amenable for targeting through metal complexation.

Synthesis, characterization and biological activity of Ni, Cu and Zn complexes of isatin hydrazones

Nickel, copper, and zinc complexes of isatin (H(2)L(1)) and N-methylisatin 3-picolinoyl hydrazone (HL(2)), were synthesized and characterized by means of spectroscopic techniques. H(2)L(1) and a nickel complex [Ni(L(2))(2)].2C(6)H(14) were also characterized by X-ray diffractometry. Biological studies, carried out in vitro on human leukemic cell lines TOM 1 and NB4, have shown that both ligands and some copper and nickel complexes are active in inhibiting cell proliferation. Compounds H(2)L(1), Cu(HL(1))(2).2H(2)O, Zn(HL(1))(2).2H(2)O inhibit DNA synthesis and act constantly with time between 0 and 72 h. The cell cycle analysis has highlighted a reduction in the number of cells in phase S of about 40%. The same compounds present only a precocious action on cell line NB4 and therefore their activity is cell target specific.

Structure and function of "metalloantibiotics"

Although most antibiotics do not need metal ions for their biological activities, there are a number of antibiotics that require metal ions to function properly, such as bleomycin (BLM), streptonigrin (SN), and bacitracin. The coordinated metal ions in these antibiotics play an important role in maintaining proper structure and/or function of these antibiotics. Removal of the metal ions from these antibiotics can cause changes in structure and/or function of these antibiotics. Similar to the case of "metalloproteins," these antibiotics are dubbed "metalloantibiotics" which are the title subjects of this review. Metalloantibiotics can interact with several different kinds of biomolecules, including DNA, RNA, proteins, receptors, and lipids, rendering their unique and specific bioactivities. In addition to the microbial-originated metalloantibiotics, many metalloantibiotic derivatives and metal complexes of synthetic ligands also show antibacterial, antiviral, and anti-neoplastic activities which are also briefly discussed to provide a broad sense of the term "metalloantibiotics."

Synthesis, characterization and X-ray structures of new antiproliferative and proapoptotic natural aldehyde thiosemicarbazones and their nickel(II) and copper(II) complexes

Synthesis and characterization of new thiosemicarbazones derived from natural aldehydes (1-9) have been investigated in order to develop a research program aimed at the development of compounds with antiviral, antibacterial, and antitumor properties. These substances contain both a chain with N and S nucleophilic centers with tuberculostatic activity, and an alkyl or terpenic moiety. In addition, a few nickel(II) and copper(II) complexes (10-18), derived also from the previously studied ligands, were synthesized and characterized by means of NMR and IR techniques. The trans-2-octenal N(1)-phenylthiosemicarbazone and its nickel complex were also characterized by X-ray diffractometry. Biological studies, performed with some of these compounds, have involved both inhibition of cell proliferation and apoptosis tests in vitro on human leukemia cell line U937 to deepen our knowledge on the way these substances interfere with biological processes in leukemic cells.

Synthesis, characterisation, X-ray structure and biological activity of three new 5-formyluracil thiosemicarbazone complexes

Three new complexes of transition metals as copper, nickel and cobalt with 5-formyluracil thiosemicarbazone (H3ut) have been synthesised and characterised by single-crystal X-ray diffraction. In all compounds the ligand behaves as SNO terdentate. In the copper complex the coordination geometry is square pyramidal with the ligand lying on the basal plane and two water molecules that complete the metal environment, the nickel compound is surrounded by six donor atoms (three of the ligand, two water oxygen atoms and a chlorine atom) in an octahedral fashion, and cobalt also shows an octahedral geometry but determined only by two terdentate ligand molecules. These three compounds have been tested on human leukemic cell lines K562 and CEM. The nickel and cobalt complexes have demonstrated low activity in cell growth, while the copper complex that is more active has been tested also on a third leukemic human cell line (U937), but it was not able to induce apoptosis on all cell lines.

Beryllium-stimulated apoptosis in macrophage cell lines

In vitro stimulation of bronchoalveolar lavage cells from patients with chronic beryllium disease (CBD) induces the production of TNF-alpha. We tested the hypothesis that beryllium (Be)-stimulated TNF-alpha might induce apoptosis in mouse and human macrophage cell lines. These cell lines were selected because they produce a range of Be-stimulated TNF-alpha. The mouse macrophage cell line H36.12j produces high levels of Be-stimulated TNF-alpha. The mouse macrophage cell line P388D.1 produces low, constitutive, levels of TNF-alpha and does not up-regulate Be-stimulated TNF-alpha production. The DEOHS-1 human CBD macrophage cell line does not produce constitutive or Be-stimulated TNF-alpha. Apoptosis was determined by microscopic observation of propidium iodide stained fragmented nuclei in unstimulated and BeSO(4)-stimulated macrophage cell lines. BeSO(4) induced apoptosis in all macrophage cell lines tested. Beryllium-stimulated apoptosis was dose-responsive and maximal after 24 h of exposure to 100 microM BeSO(4). In contrast, unstimulated and Al(2)(SO(4))(3)-stimulated macrophage cell lines did not undergo apoptosis. The general caspase inhibitor BD-fmk inhibited Be-stimulated macrophage cell line apoptosis at concentrations above 50 microM. Our data show that Be-stimulated macrophage cell line apoptosis was caspase-dependent and not solely dependent on Be-stimulated TNF-alpha levels. We speculate that the release of Be-antigen from apoptotic macrophages may serve to re-introduce Be material back into the lung microenvironment, make it available for uptake by new macrophages, and thereby amplify Be-stimulated cytokine production, promoting ongoing inflammation and granuloma maintenance in CBD.