A Photoactivated Ru (II) Polypyridine Complex Induced Oncotic Necrosis of A549 Cells by Activating Oxidative Phosphorylation and Inhibiting DNA Synthesis as Revealed by Quantitative Proteomics.

The ruthenium polypyridine complex [Ru(dppa)2(pytp)] (PF6)2 (termed as ZQX-1), where dppa = 4,7-diphenyl-1,10-phenanthroline and pytp = 4'-pyrene-2,2':6',2''-terpyridine, has been shown a high and selective cytotoxicity to hypoxic and cisplatin-resistant cancer cells either under irradiation with blue light or upon two-photon excitation. The IC50 values of ZQX-1 towards A549 cancer cells and HEK293 health cells are 0.16 ± 0.09 µM and >100 µM under irradiation at 420 nm, respectively. However, the mechanism of action of ZQX-1 remains unclear. In this work, using the quantitative proteomics method we identified 84 differentially expressed proteins (DEPs) with |fold-change| ≥ 1.2 in A549 cancer cells exposed to ZQX-1 under irradiation at 420 nm. Bioinformatics analysis of the DEPs revealed that photoactivated ZQX-1 generated reactive oxygen species (ROS) to activate oxidative phosphorylation signaling to overproduce ATP; it also released ROS and pyrene derivative to damage DNA and arrest A549 cells at S-phase, which synergistically led to oncotic necrosis and apoptosis of A549 cells to deplete excess ATP, evidenced by the elevated level of PRAP1 and cleaved capase-3. Moreover, the DNA damage inhibited the expression of DNA repair-related proteins, such as RBX1 and GPS1, enhancing photocytotoxicity of ZQX-1, which was reflected in the inhibition of integrin signaling and disruption of ribosome assembly. Importantly, the photoactivated ZQX-1 was shown to activate hypoxia-inducible factor 1A (HIF1A) survival signaling, implying that combining use of ZQX-1 with HIF1A signaling inhibitors may further promote the photocytotoxicity of the prodrug.

Merging of a Perylene Moiety Enables a RuII Photosensitizer with Long-Lived Excited States and the Efficient Production of Singlet Oxygen.

Multichromophoric systems based on a RuII polypyridine moiety containing an additional organic chromophore are of increasing interest with respect to different light-driven applications. Here, we present the synthesis and detailed characterization of a novel RuII photosensitizer, namely [(tbbpy)2 Ru((2-(perylen-3-yl)-1H-imidazo[4,5-f][1,10]-phenanthrolline))](PF6 )2 RuipPer, that includes a merged perylene dye in the back of the ip ligand. This complex features two emissive excited states as well as a long-lived (8 µs) dark state in acetonitrile solution. Compared to prototype [(bpy)3 Ru]2+ -like complexes, a strongly altered absorption (ϵ=50.3×103  M-1 cm-1 at 467 nm) and emission behavior caused by the introduction of the perylene unit is found. A combination of spectro-electrochemistry and time-resolved spectroscopy was used to elucidate the nature of the excited states. Finally, this photosensitizer was successfully used for the efficient formation of reactive singlet oxygen.

A Liposome Encapsulated Ruthenium Polypyridine Complex as a Theranostic Platform for Triple-Negative Breast Cancer.

Ruthenium coordination complexes have the potential to serve as novel theranostic agents for cancer. However, a major limitation in their clinical implementation is effective tumor accumulation. In this study, we have developed a liposome-based theranostic nanodelivery system for [Ru(phen)2dppz](ClO4)2 (Lipo-Ru). This ruthenium polypyridine complex emits a strong fluorescent signal when incorporated in the hydrophobic lipid bilayer of the delivery vehicle or in the DNA helix, enabling visualization of the therapeutic agent in tumor tissues. Incubation of MDA-MB-231 breast cancer cells with Lipo-Ru induced double-strand DNA breaks and triggers apoptosis. In a mouse model of triple-negative breast cancer, treatment with Lipo-Ru dramatically reduced tumor growth. Biodistribution studies of Lipo-Ru revealed that more than 20% of the injected dose accumulated in the tumor. These results suggest that Lipo-Ru could serve as a promising theranostic platform for cancer.

Polypyridyl ruthenium complexes with benzothiazole moiety as membrane disruptors and anti-resistance agents for Staphylococcus aureus.

Developing new antimicrobials to combat drug-resistant bacterial infections is necessary due to the increasing problem of bacterial resistance. In this study, four metallic ruthenium complexes modified with benzothiazoles were designed, synthesized and subjected to bio-evaluated. Among them, Ru-2 displayed remarkable inhibitory activity against Staphylococcus aureus (S. aureus) with a minimum inhibitory concentration (MIC) of 1.56 µg/mL. Additionally, it showcased low hemolytic toxicity (HC50 > 200 µg/mL) and the ability to effectively eradicate S. aureus without fostering drug resistance. Further investigation into the antibacterial mechanism suggested that Ru-2 may target the phospholipid component of S. aureus, leading to the disruption of the bacterial cell membrane and subsequent leakage of cell contents (nucleic acid, protein, and ONPG), ultimately resulting in the death of the bacterial cell. In vivo studies, both the G. mellonella larvae and the mouse skin infection models were conducted, indicated that Ru-2 could potentially serve as a viable candidate for the treatment of S. aureus infection. It exhibited no toxic or side effects on normal tissues. The results suggest that benzothiazole-modified ruthenium complexes may have potential as membrane-active antimicrobials against drug-resistant bacterial infections.

Design, synthesis, and evaluation of aryl-thioether ruthenium polypyridine complexes: A multi-target antimicrobial agents against gram-positive bacteria.

With the increase in bacterial resistance, new antimicrobial agents are urgently need for developing to combat multidrug-resistant pathogens and with low cytotoxicity. In this study, four new ruthenium polypyridine complexes bearing 4-tBu-phenyl sulfide Ru(bpy)2(TBPIP)](PF6)2(Ru(Ⅱ)-1), Ru(dmb)2(TBPIP)](PF6)2(Ru(Ⅱ)-2), Ru(dmob)2(TBPIP)](PF6)2(Ru(Ⅱ)-3) and Ru(dtb)2(TBPIP)](PF6)2(Ru(Ⅱ)-4) were designed, synthesized and evaluated. Those ruthenium complexes showed strong activity against Staphylococcus aureus (S. aureus) in vitro and in vivo. The Ru(Ⅱ)-1 showed excellent antimicrobial activity against Gram-positive bacteria (MIC = 2.0 µg/mL), poor hemolytic activity (HC50 > 200 µg/mL), and low cytotoxicity to mammalian cells. Ru(Ⅱ)-1 can kill bacteria quickly by destroying the bacterial membranes and avoid developing bacterial cross-resistance. Moreover, antibacterial mechanism studies show that Ru(Ⅱ)-1 destroys the integrity of bacterial cell membrane by permeabilization and depolarization of bacterial cell membrane, and interacts with bacterial DNA to produce a large number of ROS to kill bacteria. Importantly, Ru(Ⅱ)-1 exhibited effective in vivo efficacy in the mouse S. aureus infection model. These results indicated that ruthenium polypyridine complexes modified with 4-tBu-phenyl sulfide had the therapeutic potential as a novel membrane-active antimicrobial to combat Gram-positive bacterial infections.