Ruthenium-Based Photoactivated Chemotherapy

Abstract

Ruthenium(II) polypyridyl complexes form a vast family of molecules characterized by their finely tuned photochemical and photophysical properties. Their ability to undergo excited-state deactivation via photosubstitution reactions makes them quite unique in inorganic photochemistry. As a consequence, they have been used, in general, for building dynamic molecular systems responsive to light but, more particularly, in the field of oncology, as prodrugs for a new cancer treatment modality called photoactivated chemotherapy (PACT). Indeed, the ability of a coordination bond to be selectively broken under visible light irradiation offers fascinating perspectives in oncology: it is possible to make poorly toxic agents in the dark that become activated toward cancer cell killing by simple visible light irradiation of the compound inside a tumor. In this Perspective, we review the most important concepts behind the PACT idea, the relationship between ruthenium compounds used for PACT and those used for a related phototherapeutic approach called photodynamic therapy (PDT), and we discuss important questions about real-life applications of PACT in the clinic. We conclude this Perspective with important challenges in the field and an outlook.

Ruthenium Pyrazole Complexes: A Family of Highly Active Metallodrugs for Photoactivated Chemotherapy

“…These ruthenium complexes exhibit photoinduced ligand exchange in water to give ruthenium–aqua complexes that cross-link to DNA. Ruthenium complexes that undergo photosubstitution reactions are promising prodrugs for photoactivated chemotherapy (PACT) because they can potentially control the cytotoxicity spatiotemporally . As PACT agents, ruthenium complexes with polypyridyl ligands have been studied extensively by Bonnet, − Turro, − Dunbar, Glazer, − Kodanko, Papish, − and Sadler et al On the one hand, the ruthenium complexes in a triplet excited state undergo energy or electron transfer to oxygen molecules to generate reactive oxygen species.…”

Nature-Inspired Photocatalytic Azo Bond Cleavage with Red Light

“…If the bioactive component recovers its bioactivity by light-triggered BCRs, the specific caged type is called “photocaged”. Photoactivated chemotherapy (PACT) − is one of the emerging photocaged methods for treating diseases like cancer in which intracellular oxygen is no longer a necessity. Yet most reported light absorbers applied in PACT are based on noble metal compounds and have limited light absorption in the biological window.…”

A comprehensive review on singlet oxygen generation in nanomaterials and conjugated polymers for photodynamic therapy in the treatment of cancer

“…16 Considering that 1 O 2 is included in photodynamic therapy (PDT), a newly developed anticancer treatment that combines photoirradiation with photosensitizers (Sens), it is particularly interesting in biological and medical research. 17 In photodynamic therapy (PDT), 1 O 2 is the first molecule formed under aerobic conditions immediately following photoirradiation. This leads to the direct oxidation of surrounding biomolecules, the shut-down of the circulatory system, and ultimately an immune or inflammatory reaction to cancer tissue.…”