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Polyoxo-noble-metalates (PONMs), a class of molecular noble metal-oxo nanoclusters that combine features of both polyoxometalates and noble metals, are a promising platform for the development of next-generation antitumor metallodrugs. This study aimed to evaluate the antitumor potential against human neuroblastoma cells (SH-SY5Y), as well as toxicity towards healthy human peripheral blood cells (HPBCs), of five polyoxopalladates(II): (Na8[Pd13As8O34(OH)6]·42H2O (Pd13), Na4[SrPd12O6(OH)3(PhAsO3)6(OAc)3]·2NaOAc·32H2O (SrPd12), Na6[Pd13(AsPh)8O32]·23H2O (Pd13L), Na12[SnO8Pd12(PO4)8]·43H2O (SnPd12), and Na12[PbO8Pd12(PO4)8]·38H2O (PbPd12)), as the largest subset of PONMs. A pure inorganic, Pd13, was found as the most potent and selective antineuroblastoma agent with IC50 values (µM) of 7.2 ± 2.2 and 4.4 ± 1.2 for 24 and 48 h treatment, respectively, even lower than cisplatin (28.4 ± 7.4 and 11.6 ± 0.8). The obtained IC50 values (µM) for 24/48 h treatment with SrPd12 and Pd13L were 75.8 ± 6.7/76.7 ± 22.9 and 63.8 ± 3.6/21.4 ± 10.8, respectively, whereas SnPd12 and PbPd12 did not remarkably affect the SH-SY5Y viability (IC50 > > 100 µM). Pd13 caused depolarisation of inner mitochondrial membrane prior to superoxide ion hyperproduction, followed by caspase activation, DNA fragmentation and cell cycle arrest, all hallmarks of apoptotic cell death, and accompanied by an increase in acidic vesicles content, suggestive of autophagy induction. Importantly, Pd13 demonstrated the antitumor effect at concentrations not cytogenotoxic for normal HPBCs. On the contrary, SrPd12 and Pd13L at concentrations ≥ 1/3 IC50 (24 h) decreased HPBC viability and increased % tail DNA up to 42% and 3.05 times, respectively, related to control. SnPd12 and PbPd12, previously confirmed promising antileukemic agents, did not exhibit cytogenotoxicity to HPBCs, and thus could be regarded as tumor cell specific and selective drug candidates.

Background: The discovery of cisplatin and the subsequent research revealed the importance of dinitrogen-containing moiety for the anticancer action of metal complexes. Moreover, certain diamine ligands alone display cytotoxicity that contributes to the overall activity of corresponding complexes. Objective: To summarize the current knowledge on the anticancer efficacy, selectivity, and the mechanisms of action of metal complexes with various types of diamine ligands. Methods: The contribution of aliphatic acyclic, aliphatic cyclic, and aromatic diamine ligands to the anticancer activity and selectivity/toxicity of metal complexes with different metal ions were analyzed by comparison with organic ligand alone and/or conventional platinum-based chemotherapeutics. Results: The aliphatic acyclic diamine ligands are present mostly in complexes with platinum. Aliphatic cyclic diamines are part of Pt(II), Ru(II) and Au(III) complexes, while aromatic diamine ligands are found in Pt(II), Ru(II), Pd(II) and Ir(III) complexes. The type and oxidation state of metal ions greatly influences the cytotoxicity of metal complexes with aliphatic acyclic diamine ligands. Lipophilicity of organic ligands, dependent on alkyl-side chain length and structure, determines their cellular uptake, with edda and eddp/eddip ligands being most useful in this regard. Aliphatic cyclic diamine ligands improved the activity/toxicity ratio of oxaliplatin-type complexes. The complexes with aromatic diamine ligands remain unexplored regarding their anticancer mechanism. The investigated complexes mainly caused apoptotic or necrotic cell death. Conclusion: Metal complexes with diamine ligands are promising candidates for efficient and more selective alternatives to conventional platinum-based chemotherapeutics. Further research is required to reveal the chemico-physical properties and molecular mechanisms underlying their biological activity.

Melanom je visoko agresivni maligni tumor kože. Incidenca melanoma se značajno povećala u poslednjih 30 godina, stope morataliteta su visoke, a i pored napretka u hemio-/imuno-/ i radioterapiji odgovor pacijenata sa uznapredovalim stadijumom bolesti je svega 15-25%. Veliki napori se ulažu u otkrivanje, sintezu, karakterizaciju i ispitivanje mehanizma delovanja novih jedinjenja - potencijalnih antitumorskih agenasa. Među njima se izdvajaju derivati etilendiamin dipropanske kiseline, posebno etil estar cikloheksil analog etilendiamin dipropanske kiseline (EE), čiji antimelanomski efekat do sada nije detaljnije objašnjen. Cilj ovog rada je bio da se ispita citotoksični potencijal EE na ćelijskom i animalnom modelu melanoma kao i molekularni mehanizam dejstva koji EE pokreće. U eksperimentima su korišćene ćelijske linije mišjeg melanoma (B16), mišjih makrofaga (RAW264.7), humanog melanoma (518A2), humanih plućnih fibroblasta (MRC-5) i humanih keratinocita (HaCaT). Vijabilitet ćelija je ispitan testom aktivnosti kisele fosfataze, sulforodamin B testom, MTT testom i bojenjem tripan plavim, dok je integritet ćelijske membrane utvrđen testom oslobađanja laktat dehidrogenaze. Molekularni mehanizam dejstva EE na melanom miša je ispitan utvrđivanjem produkcije slobodnih kiseoničnih radikala, depolarizacije mitohondrija, aktivacije kaspaza, eksternalizacije fosfatidil serina, fragmentacije DNK i prisustva kiselih vezikula u ćelijama, korišćenjem odgovarajućih fluorohroma i analizom na protočnom citofluorimetru. Nivoi proteina značajnih za apoptozu i autofagiju su mereni imunoblot metodom. Morfološke karakteristike ćelija su ispitane fluorescentnom i transmisionom elektronskom mikroskopijom. U in vivo eksperimentima miševima soja C57Bl/6 je indukovan primarni i metastatski melanom injektiranjem B16 ćelija supkutano, odnosno intravenski. Sistemska toksičnost EE je ispitana praćenjem funkcije kostne srži, jetre i bubrega. Ispitan je efekat EE na progresiju supkutanog melanoma u po, Melanoma is a highly aggressive skin malignant tumor. The incidence of melanoma is increasing for the last 30 years, mortality is high, and despite all the improvements in chemo-/immuno- and radiotherapy the response of patients with advanced disease is as low as 15-25 %. Great efforts are put into the discovering, synthesis, characterization and investigation of molecular mechanisms of action of these compounds - potential antitumor agents. Promising new potential cytotoxic agents are derivatives of ethylene diamine dipropanoic acid, specifically ethyl ester cyclohexyl analog of ethylene diamine dipropanoic acid (EE). Its antimelanoma effect was not previously investigated and thus the aim of this research was to assess cytotoxic potential and molecular mechanism of EE's action using cell and animal melanoma models. Mouse melanoma (B16), mouse macrophages (RAW264.7), human melanoma (518A2), human pulmonary fibroblast (MRC-5) and human keratinocyte (HaCaT) cell lines were used in the experiments. Cell viability was assessed using acid phosphatase, sulphorhodamin B, MTT and trypan blue assays, whereas lactate dehydrogenase release assay was used for measuring cell membrane integrity. Molecular mechanism of action was investigated by measuring the production of reactive oxygen species, mitochondrial membrane depolarization, caspase activation, phosphatidyl serine externalization, DNA fragmentation, and number of acidic vesicles, using appropriate fluorochromes followed by flow cytometry analysis. Levels of apoptosis- and autophagy- related proteins were measured using immunoblot. Cell morphology was investigated using fluorescent and transmission electron microscopy. C57Bl/6 mice were used for in vivo experiments. Primary and metastatic melanoma were established by injecting B16 cells subcutaneously and into the tail vein of the mice. The bone marrow, liver, and kidney function were assessed for systemic toxicity of EE. The effect of EE on growth of subcutaneous melan

Melanoma, an aggressive skin tumor with high metastatic potential, is associated with high mortality and increasing morbidity. Multiple available chemotherapeutic and immunotherapeutic modalities failed to improve survival in advanced disease, and the search for new agents is ongoing. The aim of this study was to investigate antimelanoma effects of O, O-diethyl-(S, S)-ethylenediamineN, N'di-2-(3-cyclohexyl) propanoate dihydrochloride (EE), a previously synthesized and characterized organic compound. Mouse melanoma B16 cell viability was assessed using acid phosphatase, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, sulforhodamine B, and lactate dehydrogenase assays. Apoptosis and autophagy were investigated using flow cytometry, fluorescence and electron microscopy, and western blotting. In vivo antitumor potential was assessed in subcutaneous mouse melanoma model after 14 days of treatment with EE. Tumor mass and volume were measured, and RT-PCR was used for investigating the expression of autophagy-related, proapoptotic, and antiapoptotic molecules in tumor tissue. Investigated organic compound exerts significant cytotoxic effect against B16 cells. EE induced apoptosis, as confirmed by phosphatidyl serine externalisation, caspase activation, and ultrastructural features typical for apoptosis seen on fluorescence and electron microscopes. The apoptotic mechanism included prompt disruption of mitochondrial membrane potential and oxidative stress. No autophagy was observed. Antimelanoma action and apoptosis induction were confirmed in vivo, as EE decreased mass and volume of tumors, and increased expression of several proapoptotic genes. EE possesses significant antimelanoma action and causes caspasedependent apoptosis mediated by mitochondrial damage and reactive oxygen species production. Decrease in tumor growth and increase in expression of proapoptotic genes in tumor tissue suggest that EE warrants further investigation as a candidate agent in tre

Melanoma, an aggressive skin tumor with high metastatic potential, is associated with high mortality and increasing morbidity. Multiple available chemotherapeutic and immunotherapeutic modalities failed to improve survival in advanced disease, and the search for new agents is ongoing. The aim of this study was to investigate antimelanoma effects of O,O-diethyl-(S,S)-ethylenediamine-N,N'di-2-(3-cyclohexyl) propanoate dihydrochloride (EE), a previously synthesized and characterized organic compound. Mouse melanoma B16 cell viability was assessed using acid phosphatase, 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, sulforhodamine B, and lactate dehydrogenase assays. Apoptosis and autophagy were investigated using flow cytometry, fluorescence and electron microscopy, and western blotting. In vivo antitumor potential was assessed in subcutaneous mouse melanoma model after 14 days of treatment with EE. Tumor mass and volume were measured, and RT-PCR was used for investigating the expression of autophagy-related, proapoptotic, and antiapoptotic molecules in tumor tissue. Investigated organic compound exerts significant cytotoxic effect against B16 cells. EE induced apoptosis, as confirmed by phosphatidyl serine externalisation, caspase activation, and ultrastructural features typical for apoptosis seen on fluorescence and electron microscopes. The apoptotic mechanism included prompt disruption of mitochondrial membrane potential and oxidative stress. No autophagy was observed. Antimelanoma action and apoptosis induction were confirmed in vivo, as EE decreased mass and volume of tumors, and increased expression of several proapoptotic genes. EE possesses significant antimelanoma action and causes caspase-dependent apoptosis mediated by mitochondrial damage and reactive oxygen species production. Decrease in tumor growth and increase in expression of proapoptotic genes in tumor tissue suggest that EE warrants further investigation as a candidate agent in trea

This study presents the synthesis, characterization, and antitumor action of five new Pt(II) halogenido, chlorido, and iodido complexes with edda type of ligands. (S,S)-Ethylenediamine-N,N-di-2-(3-cyclohexyl)propanoic acid dihydrochloride and its methyl, ethyl, and n-propyl esters were prepared according to the previously reported procedure. All investigated complexes were characterized by IR, ESI-MS (H-1, C-13, and HMBC) NMR spectroscopy, and elemental analysis. Their cytotoxic action was investigated in four human tumor cell lines: promyelocytic (HL-60) and lymphocytic (REH) leukemia, glioma (U251), and lung carcinoma (H460). Cell viability was assessed by acid phosphatase and LDH assay, while oxidative stress and cell death parameters were analyzed by flow cytometry. The results showed that novel Pt(II) complexes exhibited antitumor action superior to precursor ligands, with iodido complexes being more efficient than corresponding chlorido complexes. Human promyelocytic cell line (HL-60) was the most sensitive to antitumor action of all investigated substances and was used for investigation of the underlying mode of antileukemic action. The investigated Pt(II) complexes showed more potent antileukemic action than corresponding Pt(IV) complex, through induction of oxidative stress and apoptosis, evidenced by caspase (8, 9, and 3) activation and phosphatidylserine externalization.

We investigated the cytotoxicity of recently synthesized (S,S)-ethyleridiamine-N,N'-di-2-(3-cyclohexyl)propanoic acid esters toward human leukemic cell lines and healthy blood mononuclear cells. Cell viability was assessed by acid phosphatase assay, apoptosis, and differentiation were analyzed by flow cytometry and electron microscopy, while intracellular localization of apoptosis-inducing factor (AIF) was determined by immunoblotting. It was demonstrated that methyl, ethyl, and n-propyl esters were toxic to HL-60, REH, MOLT-4, KG-1, JVM-2, and K-562 leukemic cell lines, while the nonesterified parental compound and n-butyl ester were devoid of cytotoxic action. The ethyl ester exhibited the highest cytotoxic activity (IC50 10.7 mu M-45.4 mu M), which was comparable to that of the prototypical anticancer drug cisplatin. The observed cytotoxic effect in HL-60 cells was associated with an increase in superoxide production and mitochondrial membrane depolarization, leading to apoptotic cell death characterized by phosphatidylserine externalization and DNA fragmentation in the absence of autophagic response. DNA fragmentation preceded caspase activation and followed AIF translocation from mitochondria to nucleus, which was indicative of caspase-independent apoptotic cell death. HL-60 cells treated with subtoxic concentration of the compound displayed morphological signs of granulocytic differentiation (nuclear indentations and presence of cytoplasmic primary granules), as well as an increased expression of differentiation markers CD11b and CD15. The cyclohexyl analogues of ethylenediamine dipropanoic acid were also toxic to peripheral blood mononuclear cells of both healthy controls and leukemic patients, the latter being more sensitive. Our data demonstrate that the toxicity of the investigated cyclohexyl compounds against leukemic cell lines is mediated by caspase-independent apoptosis associated with oxidative stress, mitochondrial dysfunction, and AIF translocation.