Photocytotoxicity of a New Rh₂(II,II) Complex:  Increase in Cytotoxicity upon Irradiation Similar to That of PDT Agent Hematoporphyrin

Abstract

A new type of heteroleptic dirhodium complex cis-[Rh(2)(mu-O2CCH3)2-(bpy)(dppz)]2+ (3) was synthesized and its potential as a photodynamic therapy (PDT) agent was investigated. Although 27% hypochromicity of the absorption of 3 in the near-UV and visible regions is observed in the presence of duplex DNA, relative viscosity measurements reveal that the complex does not intercalate between the DNA bases. The DNA photocleavage with visible light by 3 proceeds via both oxygen dependent and independent mechanisms, and it is more efficient than that of related complexes. The increase in the cytotoxicity of 3 towards human skin cells is similar to that of hematoporphyrin, a key ingredient in a PDT drug currently in use. This feature makes this complex a useful candidate for further PDT studies.

Synthesis, structure, DNA binding and DNA cleavage activity of oxovanadium(IV) N-salicylidene-S-methyldithiocarbazate complexes of phenanthroline bases

“…Bleomycin is an anticancer drug that works as a chemical nuclease showing oxidative cleavage of DNA [21,22]. There are recent reports of transition metal complexes cleaving DNA on photo-irradiation in visible light [23][24][25][26][27][28][29][30]. The complexes showing facile visible light-induced cleavage of DNA are of interest in the chemistry of photodynamic therapy (PDT) of cancer [7,8].…”

Photoactivated Biological Activity of Transition‐Metal Complexes

“…In the dark, it is almost inactive with an IC 50 values of (208 Ϯ 10) µ, whereas after irradiation, a significant cytotoxicity is observed with an IC 50 value of (44 Ϯ 2) µ. [42] www.eurjic.org 2+ , which gives rise to three different isomeric species. [43] These cause reduced mobility of linear plasmid DNA in an agarose gel electrophoresis experiment, which is evidence for the formation of covalent adducts.…”

Interactions of Metal—Metal‐Bonded Antitumor Active Complexes with DNA Fragments and DNA

“…60 Likewise, the cytotoxicity of the heteroleptic species cis-[Rh 2 -(µ-O 2 CCH 3 ) 2 (bpy)(dppz)] 2+ ( Figure 17) increases 5-fold upon irradiation, with the advantage of 10-fold lower toxicity than hematoporphyrin (key component in Photofrin) in the dark. 61 These results render the aforementioned compounds promising candidates for photochemotherapy.…”