Combination of Ru(<scp>ii</scp>) complexes and light: new frontiers in cancer therapy

TLDR

Photodynamic therapy (PDT) combines light, oxygen, and a photosensitizer, yet only two of the thirteen clinically approved cancer PSs contain a metal ion, despite the widespread use of platinum drugs in chemotherapy. This perspective reviews the opportunities of Ru(II) complexes as photosensitizers in PDT and their recent successes in photoactivated chemotherapy (PACT). Ru(II) complexes enable a photoactivated chemotherapy strategy that generates cell toxicity without oxygen, addressing the hypoxic nature of tumors.

Abstract

The synergistic action of light, oxygen and a photosensitizer (PS) has found applications for decades in medicine under the name of photodynamic therapy (PDT) for the treatment of skin diseases and, more recently, for the treatment of cancer. However, of the thirteen PSs currently approved for the treatment of cancer over more than 10 countries, only two contain a metal ion. This fact is rather surprising considering that nowadays around 50% of conventional chemotherapies involve the use of cisplatin and other platinum-containing drugs. In this perspective article, we review the opportunities brought by the use of Ru(ii) complexes as PSs in PDT. In addition, we also present the recent achievements in the application of Ru(ii) complexes in photoactivated chemotherapy (PACT). In this strategy, the presence of oxygen is not required to achieve cell toxicity. This is of significance since tumors are generally hypoxic. Importantly, this perspective article focuses particularly on the Ru(ii) complexes for which an