Improving In Vivo Tumor Accumulation and Efficacy of Platinum Antitumor Agents by Electronic Tuning of the Kinetic Lability

Kinetically Inert Platinum (II) Complexes for Improving Anticancer Therapy: Recent Developments and Road Ahead

The search for better chemotherapeutic drugs to alleviate the deficiencies of existing platinum (Pt) drugs has picked up the pace in the millennium. There has been a disparate effort to design better and safer Pt drugs to deal with the problems of deactivation, Pt resistance and toxic side effects of clinical Pt drugs. In this review, we have discussed the potential of kinetically inert Pt complexes as an emerging class of next-generation Pt drugs. The introduction gives an overview about the development, use, mechanism of action and side effects of clinical Pt drugs as well as the various approaches to improve some of their pharmacological properties. We then describe the impact of kinetic lability on the pharmacology of functional Pt drugs including deactivation, antitumor efficacy, toxicity and resistance. Following a brief overview of numerous pharmacological advantages that a non-functional kinetically inert Pt complex can offer; we discussed structurally different classes of kinetically inert Pt (II) complexes highlighting their unique pharmacological features.

Cytotoxic Pt(II) complexes containing alizarin: a selective carrier for DNA metalation

Many efforts have been made in the last few decades to selectively transport antitumor agents to their potential target sites with the aim to improve efficacy and selectivity. Indeed, this aspect could greatly improve the beneficial effects of a specific anticancer agent especially in the case of orphan tumors like the triple negative breast cancer. A possible strategy relies on utilizing a protective leaving group like alizarin as the Pt(II) ligand to reduce the deactivation processes of the pharmacophore enacted by Pt resistant cancer cells. In this study a new series of neutral mixed-ligand Pt(II) complexes bearing alizarin and a variety of diamine ligands were synthesized and spectroscopically characterized by FT-IR, NMR and UV-Vis analyses. Three Pt(II) compounds, i.e., 2b, 6b and 7b, emerging as different both in terms of structural properties and cytotoxic effects (not effective, 10.49 ± 1.21 μM and 24.5 ± 1.5 μM, respectively), were chosen for a deeper investigation of the ability of alizarin to work as a selective carrier. The study comprises the in vitro cytotoxicity evaluation against triple negative breast cancer cell lines and ESI-MS interaction studies relative to the reaction of the selected Pt(II) complexes with model proteins and DNA fragments, mimicking potential biological targets. The results allow us to suggest the use of complex 6b as a prospective anticancer agent worthy of further investigations.