Metal-based antitumor drugs play a relevant role in antiblastic chemotherapy. Cisplatin is regarded as one of the most effective drugs, even if severe toxicities and drug resistance phenomena limit its clinical use. Therefore, in recent years there has been a rapid expansion in research and development of novel metal-based anticancer drugs to improve clinical effectiveness, to reduce general toxicity and to broaden the spectrum of activity. The variety of metal ion functions in biology has stimulated the development of new metallodrugs other than Pt drugs with the aim to obtain compounds acting via alternative mechanisms of action. Among non-Pt compounds, copper complexes are potentially attractive as anticancer agents. Actually, since many years a lot of researches have actively investigated copper compounds based on the assumption proposal that endogenous metals may be less toxic. It has been established that the properties of copper-coordinated compounds are largely determined by the nature of ligands and donor atoms bound to the metal ion. In this review, the most remarkable achievements in the design and development of copper(I, II) complexes as antitumor agents are discussed. Special emphasis has been focused on the identification of structure-activity relationships for the different classes of copper(I,II) complexes. This work was motivated by the observation that no comprehensive surveys of copper complexes as anticancer agents were available in the literature. Moreover, up to now, despite the enormous efforts in synthesizing different classes of copper complexes, very few data concerning the molecular basis of the mechanisms underlying their antitumor activity are available. This overview, collecting the most significant strategies adopted in the last ten years to design promising anticancer copper(I,II) compounds, would be a help to the researchers working in this field.

Copper complexes as anticancer agents

Synthesis, X-ray crystal structures and biomimetic and anticancer activities of novel copper(II)benzoate complexes incorporating 2-(4'-thiazolyl)benzimidazole (thiabendazole), 2-(2-pyridyl)benzimidazole and 1,10-phenanthroline as chelating nitrogen donor ligands.

The complexes [Cu(salH)(2)(H(2)O)] (1), [Cu(dipsH)(2)(H(2)O)] (2), {Cu(3-MeOsal)(H(2)O)(0.75)}(n) (3), [Cu(dipsH)(2)(BZDH)(2)] (4), [Cu(dipsH)(2)(2-MeOHBZDH)(2)]·EtOH (5), [Cu(sal)(phen)] (6), [Cu(dips)(phen)]·H(2)O (7), and [Cu(3-MeOsal)(phen)]·H(2)O (8) (salH(2) = salicylic acid; dipsH(2) = 3,5-diisopropylsalicylic acid; 3-MeOsalH(2) = 3-methoxysalicylic acid; BZDH = benzimidazole; 2-MeOHBZDH = 2 methanolbenzimidazole and phen =1,10-phenanthroline) were prepared and characterized. Structures of 4, 5, and 8 were determined by X-ray crystallography. Compounds 1-8 are potent superoxide dismutase mimetics, and they are inactive as inhibitors of COX-2 activity. Compounds 1, 4, and 5 exhibit moderate inhibition of COX-1. Complexes 6-8 display rapid micromolar cytotoxicity against cisplatin sensitive (breast (MCF-7), prostate (DU145), and colon (HT29)) and cisplatin resistant (ovarian (SK-OV-3)) cell lines compared to 1-5, and they exhibit potent in vitro DNA binding and cleavage capabilities.

Copper(II) Complexes of Salicylic Acid Combining Superoxide Dismutase Mimetic Properties with DNA Binding and Cleaving Capabilities Display Promising Chemotherapeutic Potential with Fast Acting in Vitro Cytotoxicity against Cisplatin Sensitive and Resistant Cancer Cell Lines

Synthesis, structure and biological activities of cobalt(II) and zinc(II) coordination compounds with 2-benzimidazole derivatives.

Synthesis, catalase, superoxide dismutase and antitumour activities of copper(II) carboxylate complexes incorporating benzimidazole, 1,10-phenanthroline and bipyridine ligands : X-ray crystal structures of [Cu (BZA )2(bipy ) (H2O ) ], [Cu(SalH)2(BZDH)2] and [Cu (CH3COO )2(5,6 -DMBZDH )2] (SalH2 = salicylic acid; BZAH = benzoic acid; BZDH = benzimidazole and 5,6-DMBZDH = 5,6-dimethylbenzimidazole)

Synthesis, antimicrobial activity and chemotherapeutic potential of inorganic derivatives of 2-(4'-thiazolyl)benzimidazole[thiabendazole]: X-ray crystal structures of [Cu(TBZH)2Cl]Cl.H2O.EtOH and TBZH2NO3 (TBZH=thiabendazole).

Synthesis and in vitro anti-microbial activity of manganese (II) complexes of 2,2-dimethylpentanedioic and 3,3-dimethylpentanedioic acid: X-ray crystal structure of [Mn(3dmepda)(phen)2] · 7.5H2O (3dmepdaH2=3,3-dimethylpentanedioic acid and phen=1,10-phenanthroline)

Denis O Shea

Papers

Synthesis, X-ray crystal structures and biomimetic and anticancer activities of novel copper(II)benzoate complexes incorporating 2-(4'-thiazolyl)benzimidazole (thiabendazole), 2-(2-pyridyl)benzimidazole and 1,10-phenanthroline as chelating nitrogen donor ligands.

Synthesis, antimicrobial activity and chemotherapeutic potential of inorganic derivatives of 2-(4'-thiazolyl)benzimidazole[thiabendazole]: X-ray crystal structures of [Cu(TBZH)2Cl]Cl.H2O.EtOH and TBZH2NO3 (TBZH=thiabendazole).

Synthesis and in vitro anti-microbial activity of manganese (II) complexes of 2,2-dimethylpentanedioic and 3,3-dimethylpentanedioic acid: X-ray crystal structure of [Mn(3dmepda)(phen)2] · 7.5H2O (3dmepdaH2=3,3-dimethylpentanedioic acid and phen=1,10-phenanthroline)