Mo(II) complexes: a new family of cytotoxic agents?

Several molybdenum complexes, [Mo(η(3)-C(3)H(5))X(CO)(2)(N-N)] (N-N = 1,10-phenanthroline, phen: X = CF(3)SO(3)T1, X = Br B1, X = Cl C1; N-N = 2,2'-bipyridyl, X = CF(3)SO(3)T2, X = Br B2) and [W(η(3)-C(3)H(5))Br(CO)(2)(phen)] (W1) have been synthesized and characterized. Their antitumor properties have been tested in vitro against human cancer cell lines cervical carcinoma (HeLa) and breast carcinoma (MCF-7) using a metabolic activity test (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, MTT), leading to IC(50) values ranging from 3 to 45 μM, approximately. Most complexes exhibited significant antitumoral activity. Complexes B1 and T2 were chosen for subsequent studies aiming to understand their mechanism of action. Cellular uptake of molybdenum and octanol/water partition assays revealed that both B1 and T2 exhibit a selective uptake by cells and intermediate partition coefficients. The binding constants of B1 and T2 with ct DNA, as determined by absorption titration, are 2.08 (± 0.98) × 10(5) and 3.68 (± 2.01)x 10(5)M(-1), respectively. These results suggest that they interact with DNA changing its conformation and possibly inducing cell death, and may therefore provide a valuable tool in cancer chemotherapy.