Glassy carbon electrodes deliver unpredictable reduction potentials for platinum(IV) antitumor prodrugs

Targeting drug delivery system for platinum(Ⅳ)-Based antitumor complexes

Classical platinum(II) anticancer agents are widely-used chemotherapeutic drugs in the clinic against a range of cancers. However, severe systemic toxicity and drug resistance have become the main obstacles which limit their application and effectiveness. Because divalent cisplatin analogues are easily destroyed in vivo, their bioavailability is low and no selective to tumor tissues. The platinum(IV) prodrugs are attractive compounds for cancer treatment because they have great advantages, e.g., higher stability in biological media, aqueous solubility and no cross-resistance with cisplatin, which may become the next generation of platinum anticancer drugs. In addition, platinum(IV) drugs could be taken orally, which could be more acceptable to cancer patients, breaking the current situation that platinum(II) drugs can only be given by injection. The coupling of platinum(IV) complexes with tumor targeting groups avoids the disadvantages such as instability in blood, irreversible binding to plasma proteins, rapid renal clearance, and non-specific distribution in normal tissues. Because of the above advantages, the combination of platinum complexes and tumor targeting groups has become the hottest field in the research and development of new platinum drugs. These approaches can be roughly categorized into two groups: active and passive targeted strategies. This review concentrates on various targeting and delivery strategies for platinum(IV) complexes to improve the efficacy and reduce the side effects of platinum-based anticancer drugs. We have made a summary of the related articles on platinum(IV) targeted delivery in recent years. We believe the results of the studies described in this review will provide new ideas and strategies for the development of platinum drugs.

Elusive Intermediates in the Breakdown Reactivity Patterns of Prodrug Platinum(IV) Complexes

Kinetically inert platinum(IV) complexes are receiving growing attention as promising candidates in the effort to develop safe and valid alternatives to classical square-planar Pt(II) complexes currently used in antineoplastic therapy. Their antiproliferative activity requires intracellular Pt(IV)-Pt(II) reduction (activation by reduction). In the present work, a set of five Pt(IV) complexes has been assayed using mass spectrometry-based techniques, i.e., collision-induced dissociation (CID), and IR multiple photon dissociation (IRMPD) spectroscopy, together with ab initio theoretical investigations. Breakdown and reduction mechanisms are observed that lead to Pt(II) species. Evidence is found for typically transient Pt(III) intermediates along the dissociation paths of isolated, negatively charged (electron-rich) Pt(IV) prodrug complexes.

Design and synthesis of a new series of low toxic naphthalimide platinum(IV) antitumor complexes with dual DNA damage mechanism

Naphthalimide platinum(IV) antitumor complexes with potential dual DNA damage mechanism were designed, synthesized and evaluated for antitumor activities. The incorporation of DNA targeted naphthalimide group to the platinum(IV) system exerts much positive impacts on their antitumor efficacy. The mechanism research reveals that the title compounds could interact with dsDNA in platinum(IV) form via the naphthalimide group and cause DNA lesion. The further reduction would release platinum(II) complexes and naphthalimide acids which would induce remarkable secondary damage to DNA. Furthermore, the naphthalimide platinum(IV) compounds could combine with human serum albumin via electrostatic force, which are favourable for their storage and transport in blood. Moreover, the title compounds exhibit higher accumulation in tumor cells, and exert lower toxic and higher safe properties than oxaliplatin in vivo.