Antitumor activity via apoptotic cell death pathway of water soluble copper(II) complexes: effect of the diamino unit on selectivity against lung cancer NCI-H460 cell line.

The cytotoxicity against five human tumor cell lines (THP-1, U937, Molt-4, Colo-205 and NCI-H460) of three water soluble copper(II) coordination compounds containing the ligands 3,3'-(ethane-1,2-diylbis(azanediyl))dipropanamide (BCEN), 3,3'-(piperazine-1,4-diyl)dipropanamide (BPAP) or 3,3'-and (1,4-diazepane-1,4-diyl)dipropanamide (BPAH) are reported in this work. The ligands contain different diamine units (ethylenediamine, piperazine or homopiperazine) and two propanamide units attached to the diamine centers, resulting in N2O2 donor sets. The complex containing homopiperazine unit presented the best antiproliferative effect and selectivity against lung cancer cell line NCI-H460, showing inhibitory concentration (IC50) of 58 µmol dm-3 and Selectivity Index (SI) > 3.4. The mechanism of cell death promoted by the complex was investigated by Sub-G1 cell population analysis and annexin V and propidium iodide (PI) labeling techniques, suggesting that the complex promotes death by apoptosis. Transmission electron microscopy investigations are in agreement with the results presented by mitochondrial membrane potential analysis and also show the impairment of other organelles, including endoplasmic reticulum.

In vitro and in vivo studies of the antineoplastic activity of copper (II) compounds against human leukemia THP-1 and murine melanoma B16-F10 cell lines.

We investigated the antineoplastic activities of a previously reported copper (II) coordination compound, [Cu(BMPA)Cl2]CH3OH (1), and a new compound, [Cu(HBPA)Cl2]H2O (2), where BMPA is bis(pyridin-2-ylmethyl)amine and HBPA is (2-hydroxybenzyl)(2-pyridylmethyl)amine, using various cellular models of human leukemia (THP-1, U937, HL60, Molt-4, JURKAT) and human colon cancer (COLO 205), as well as a murine highly metastatic melanoma (B16-F10) cell line. Compound (2) was characterized using several physical and chemical techniques, including X-ray diffraction studies. The IC50 values of the copper coordination complexes in the human leukemia cell lines ranged from 87.63 ± 1.02 to ≥400 µM at high cell concentrations and from 19.17 ± 1.06 to 97.67 ± 1.23 µM at low cell concentrations. Both compounds induced cell death, which was determined by cell cycle analyses and phosphatidylserine exposure studies. THP-1 cells released cytochrome c to the cytoplasm 12 h after treatment with 400 µM of compound (2). To evaluate the apoptosis pathway induced by compound (2), we measured the activities of initiator caspases 8 and 9 and executioner caspases 3 and 6. The results were suggestive of the activation of both intrinsic and extrinsic apoptosis pathways. To investigate the activities of the compounds in vivo, we selected two sensitive cell lines from leukemia (THP-1) and solid tumor (B16-F10) lineages. BALB/c nude bearing THP-1 tumors treated with 12 mg·kg(-1) of compound (2) showed a 92.4% inhibition of tumor growth compared with the control group.

Synthesis, characterization and antitumoral activity of new cobalt(II)complexes: Effect of the ligand isomerism on the biological activity of the complexes.

The synthesis, physico-chemical characterization and cytotoxicity against five human tumoral cell lines (THP-1, U937, Molt-4, Colo205 and H460) of three new cobalt(II) coordination compounds are reported (i.e. Co(HL1)Cl (1), Co(HL2)Cl (2) and [Co(HL3)Cl]0.0.5 (CH3)2CHOH (3)). H2L2 (2-{[[2-hydroxy-3-(1-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) and H2L3 (2-{[[2-hydroxy-3-(2-naphthyloxy)propyl](pyridin-2-ylmethyl)amino]methyl}phenol) present α and ß-naphthyl groups respectively, which is absent in H2L1 (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine. These compounds were characterized by a range of physico-chemical methods. X-ray diffraction studies were performed for complex (3), indicating the formation of a mononuclear complex. Complexes (2) and (3), which contain α and ß-naphthyl groups respectively, have presented lower IC50 values than those exhibited by complex (1). Complex (3) presents IC50 values lower than cisplatin against Colo205 (90 and 196µmolL(-1), respectively) and H460 (147 and 197µmolL(-1), respectively). These human neoplastic cells under investigation were also more susceptible toward complex (3) than peripheral blood mononuclear cells. Transmission electron microscopy investigations are in agreement with the loss of mitochondrial membrane potential (ΔΨm) observed by JC-1 mitochondrial potential sensor and indicate that the activity of complex (3) against leukemic cell line (U937) is mediated by an apoptotic mechanism associated with mitochondrial dysfunction (intrinsic pathway).

Induction of apoptosis in leukemia cell lines by new copper(II) complexes containing naphthyl groups via interaction with death receptors.

The synthesis, physico-chemical characterization and cytotoxicity of four new ligands and their respective copper(II) complexes toward two human leukemia cell lines (THP-1 and U937) are reported (i.e. [(HL1)Cu(µ-Cl)2Cu(HL1)]Cl2·H2O (1), [(H2L2)Cu(µ-Cl)2Cu(H2L2)]Cl2·5H2O (2), [(HL3)Cu(µ-Cl)2Cu(HL3)]Cl2·4H2O (3), [(H2L4)Cu(µ-Cl)2Cu(H2L4)]Cl2·6H2O (4)). Ligands HL1 and HL3 contain two pyridines, amine and alcohol moieties with a naphthyl pendant unit yielding a N3O coordination metal environment. Ligands H2L2 and H2L4 have pyridine, phenol, amine and alcohol groups with a naphthyl pendant unit providing a N2O2 coordination metal environment. These compounds are likely to be dinuclear in the solid state but form mononuclear species in solution. The complexes have an antiproliferative effect against both leukemia cell lines; complex (2) exhibits higher activity than cisplatin against U937 (8.20 vs 16.25µmoldm(-3)) and a comparable one against THP-1. These human neoplastic cells are also more susceptible than peripheral blood mononuclear cells (PBMCs) toward the tested compounds. Using C57BL/6 mice an LD50 of 55mgkg(-1) was determined for complex (2), suggesting that this compound is almost four times less toxic than cisplatin (LD50=14.5mgkg(-1)). The mechanism of cell death promoted by ligand H2L2 and by complexes (2) and (4) was investigated by a range of techniques demonstrating that the apoptosis signal triggered at least by complex (2) starts from an extrinsic pathway involving the activation of caspases 4 and 8. This signal is amplified by mitochondria with the concomitant release of cytochrome c and the activation of caspase 9.

Synthesis, characterization and antibacterial activity of FeIII, CoII, CuII and ZnII complexes probed by transmission electron microscopy.

We synthesized iron(III), cobalt(II), copper(II) and zinc(II) complexes [Fe(III)(HBPClNOL)Cl(2)]·H(2)O (1), [Co(II)(H(2)BPClNOL)Cl(2)] (2), [Cu(II)(H(2)BPClNOL)Cl]Cl·H(2)O (3), and [Zn(II)(HBPClNOL)Cl] (4), where H(2)BPClNOL is the ligand (N-(2-hydroxybenzyl)-N-(2-pyridylmethyl)[(3-chloro)(2-hydroxy)]propylamine). The complexes obtained were characterized by elemental analysis, IR and UV-visible spectroscopies, electrospray ionization mass spectrometry (ESI-MS), tandem mass spectrometry (MS/MS), and cyclic voltammetry. X-ray diffraction studies were performed for complexes (3) and (4) revealing the presence of mononuclear and dinuclear structures in solid state for (3). However, the zinc complex is mononuclear in solid state. Biological studies of complexes (1)-(4) were carried out in vitro for antimicrobial activity against nine Gram-positive bacteria (Staphylococcus aureus strains RN 6390B, COL, ATCC 25923, Smith Diffuse, Wood 46, enterotoxigenic S. aureus FRI-100 (SEA+), FRI S-6 (SEB+) and SEC FRI-361) and animal strain S. aureus LSA 88 (SEC/SED/TSST-1+). The following sequence of inhibition promoted by the complexes was observed: (4)>(2)>(3)>(1), showing the effect of the metal on the biological activity. To directly observe the morphological changes of the internal structure of bacterial cells after the treatment, transmission electron microscopy (TEM) was employed. For the most active complex [Zn(II)(HBPClNOL)Cl] (4), granulation deposits around the genetic material and internal material leaking were clearly detected.

Catalase vs peroxidase activity of a manganese(II) compound: identification of a Mn(III)-(mu-O)(2)-Mn(IV) reaction intermediate by electrospray ionization mass spectrometry and electron paramagnetic resonance spectroscopy.

Herein, we report reactivity studies of the mononuclear water-soluble complex [Mn(II)(HPClNOL)(eta(1)-NO(3))(eta(2)-NO(3))] 1, where HPClNOL = 1-(bis-pyridin-2-ylmethyl-amino)-3-chloropropan-2-ol, toward peroxides (H(2)O(2) and tert-butylhydroperoxide). Both the catalase (in aqueous solution) and peroxidase (in CH(3)CN) activities of 1 were evaluated using a range of techniques including electronic absorption spectroscopy, volumetry (kinetic studies), pH monitoring during H(2)O(2) disproportionation, electron paramagnetic resonance (EPR), electrospray ionization mass spectrometry in the positive ion mode [ESI(+)-MS], and gas chromatography (GC). Electrochemical studies showed that 1 can be oxidized to Mn(III) and Mn(IV). The catalase-like activity of 1 was evaluated with and without pH control. The results show that the pH decreases when the reaction is performed in unbuffered media. Furthermore, the activity of 1 is greater in buffered than in unbuffered media, demonstrating that pH influences the activity of 1 toward H(2)O(2). For the reaction of 1 with H(2)O(2), EPR and ESI(+)-MS have led to the identification of the intermediate [Mn(III)Mn(IV)(mu-O)(2)(PClNOL)(2)](+). The peroxidase activity of 1 was also evaluated by monitoring cyclohexane oxidation, using H(2)O(2) or tert-butylhydroperoxide as the terminal oxidants. Low yields (<7%) were obtained for H(2)O(2), probably because it competes with 1 for the catalase-like activity. In contrast, using tert-butylhydroperoxide, up to 29% of cyclohexane conversion was obtained. A mechanistic model for the catalase activity of 1 that incorporates the observed lag phase in O(2) production, the pH variation, and the formation of a Mn(III)-(mu-O)(2)-Mn(IV) intermediate is proposed.