Photobiological Impact of [{(bpy)₂Ru(dpp)}₂RhCl₂]Cl₅ and [{(bpy)₂Os(dpp)}₂RhCl₂]Cl₅ [bpy = 2,2‘-Bipyridine; dpp = 2,3-Bis(2-pyridyl)pyrazine] on Vero Cells

Abstract

The in vitro photobiology of the supramolecular complexes [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and [{(bpy)2Os(dpp)}2RhCl2]Cl5 [bpy=2,2'-bipyridine; dpp=2,3-bis(2-pyridyl)pyrazine] with African green monkey kidney epithelial (Vero) cells was investigated. Previously, the complexes have been shown to photocleave DNA in the presence or absence of O2. Vero cell replication was uninhibited for cells exposed to the metal complex but protected from light. Vero cells that were exposed to metal complex, rinsed, and illuminated with >460 nm light showed a replication response that was metal complex concentration-dependent. Vero cells exposed to 3.0-120 microM [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and illuminated showed inhibition of cell growth, with evidence of cell death seen for complex concentrations>or=10 microM. Cells exposed to [{(bpy)2Os(dpp)}2RhCl2]Cl5 at concentrations of 5.5-110 microM, rinsed, and illuminated showed only inhibition of cell growth. The impact of [{(bpy)2Ru(dpp)}2RhCl2]Cl5 and [{(bpy)2Os(dpp)}2RhCl2]Cl5 on cell growth following illumination shows the promise of this new structural motif as a photodynamic therapy agent.

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].…”

Nuclear targeting terpyridine iron(II) complexes for cellular imaging and remarkable photocytotoxicity

“…Using a PDT approach in cancer chemotherapy, Sadler and co-workers showed that a sixcoordinate platinum(IV) complex as a photoactive metallodrug with two trans-azide ligands is stable in the dark but forms a diguanidine platinum(II) adduct on photo-activation, killing human cancer cells [18]. Significant results in the PDT chemistry also include dirhodium(II, II) complexes showing photocytotoxic effects in visible light in different cancer cell lines under both aerobic and anaerobic medium and ruthenium nitrosyl complexes that are shown to be potent PDT agents for sitespecific delivery of cytotoxic nitric oxide (NO) on photo-irradiation [7,8,[19][20][21][22]. Photodynamic therapy using metal complexes can traverse from a concept to reality if only the dark toxicity of the complex can be kept low compared to its phototoxicity.…”

Photoactivated Biological Activity of Transition‐Metal Complexes

“…[25] A related compound with a RhCl 2 group complexed by two Ru(bpy) 2 (dpp) groups {dpp = 2,3-bis(2-pyridyl)pyrazine} was even tested on Vero cells in vitro and showed evidence for cell death at concentrations above 10 µ after illumination at Ͼ460 nm, whereas it was inactive when incubated in the dark (Figure 2b,c). [26,27] Normally, excitation in metal-to-ligand charge transfer (MLCT) bands below 500 nm is used to initiate photoreactions of Ru II complexes. For therapeutic applications, however, a longer excitation wavelength is highly desirable due to deeper tissue penetration in the near-IR region.…”