Ruthenium(II) and copper(II) polyamine complexes as promising antitumor agents: synthesis, characterization, and biological evaluation.

Ruthenium or copper complexes have emerged as some of the most promising alternatives for the treatment of many types of cancer. They have enhanced activity, greater selectivity and reduced side effects compared to their predecessors, cisplatin and its analogues. On the other hand, polyamine metabolism is often deregulated in cancer, leading to increased intracellular concentrations of polyamines that promote cell proliferation, differentiation, and tumorigenesis. In the present work, we report the synthesis and characterization of a family of mono- and binuclear Ru(II) and Cu(II) complexes functionalized with polyamine ligands derived from norspermine. The computer-aided analysis of the electron paramagnetic resonance (EPR) spectra provided magnetic and dynamic parameters, which helped to identify prevalent Cu-N2 coordination in a partially distorted square planar geometry of the Cu(II) complexes and the flexibility of the complexes in solution, slowed down by both the complex size and the hydrophobic interactions between chains. In vitro studies focused on advanced prostate cancer have demonstrated that these new metal complexes present a high level of cytotoxicity against PC3 cells. Furthermore, these metallic compounds exhibit the ability to inhibit cell adhesion and migration while reducing intracellular reactive oxygen species levels, which are key factors of metastasis.