8-Hydroxyquinoline ruthenium(II) complexes induce ferroptosis in HeLa cells by down-regulating GPX4 and ferritin

Mitochondria-localizing triphenylphosphine-8-hydroxyquinoline Ru complexes induce ferroptosis and their antitumor evaluation

Ruthenium complexes are one of the most promising anticancer drugs and ferroptosis is a novel form of regulated cell death, the study on the effect of Ru complexes on ferroptosis is helpful to find more effective antitumor drugs. Here, the synthesis and characterization of two Ru complexes containing 8-hydroxylquinoline and triphenylphosphine as ligands, [Ru(L1) (PPh3)2Cl2] (Ru-1), [Ru(L2) (PPh3)2Cl2] (Ru-2), were reported. Complexes Ru-1 ∼ Ru-2 showed good anticancer activity in Hep-G2 cells. Researches indicated that complexes Ru-1 ∼ Ru-2 could be enriched and appear as red fluorescence in the mitochondria, arouse dysfunction of mitochondria, induce the accumulation of reactive oxygen species (ROS) and lipid peroxidation (LPO), while the morphology of nuclei and cell apoptosis had no significant change. Further experiments proved that GPX4 and Ferritin were down-regulated, which eventually triggered ferroptosis in Hep-G2 cells. Remarkably, Ru-1 showed high inhibitory activity against xenograft tumor growth in vivo (TGIR = 49%). This study shows that the complex Ru-1 could act as a novel drug candidate by triggering cell ferroptosis.

Anticancer activity of 8-hydroxyquinoline-triphenylphosphine rhodium(III) complexes targeting mitophagy pathways

Metallodrugs exhibiting distinct mechanisms of action compared with cisplatin hold promise for overcoming cisplatin resistance and improving the efficacy of anticancer drugs. In this study, a new series of rhodium (Rh)(III) complexes containing tris(triphenylphosphine)rhodium(I) chloride [(TPP)3RhCl] (TPP = triphenylphosphine, TPP=O = triphenylphosphine oxide) and 8-hydroxyquinoline derivatives (H-XR1-H-XR4), namely [Rh(XR1)2(TPP)Cl]·(TPP=O) (Yulin Normal University-1a [YNU-1a]), [Rh(XR2)2(TPP)Cl] (YNU-1b), [Rh(XR3)2(TPP)Cl] (YNU-1c), and [Rh(XR4)2(TPP)Cl] (YNU-1d), was synthesized and characterized via X-ray diffraction, mass spectrometry and IR. The cytotoxicity of the compounds YNU-1a-YNU-1d in Hep-G2 and HCC1806 human cancer cell lines and normal HL-7702 cell line was evaluated. YNU-1c exhibited cytotoxicity and selectivity in HCC1806 cells (IC50 = 0.13 ± 0.06 μM, selectivity factor (SF) = 384.6). The compounds YNU-1b and YNU-1c, which were selected for mechanistic studies, induced the activation of apoptotic pathways and mitophagy. In addition, these compounds released cytochrome c, cleaved caspase-3/pro-caspase-3 and downregulated the levels of mitochondrial respiratory chain complexes I/IV (M1 and M4) and ATP. The compound YNU-1c, which was selected for in vivo experiments, exhibited tumor growth inhibition (58.9 %). Importantly, hematoxylin and eosin staining and TUNEL revealed that HCC1806 tumor tissues exhibited significant apoptotic characteristics. YNU-1a-YNU-1d compounds are promising drug candidates that can be used to overcome cisplatin resistance.

The uses of zebrafish (Danio rerio) as an in vivo model for toxicological studies: A review based on bibliometrics

An in vivo model is necessary for toxicology. This review analyzed the uses of zebrafish (Danio rerio) in toxicology based on bibliometrics. Totally 56,816 publications about zebrafish from 2002 to 2023 were found in Web of Science Core Collection, with Toxicology as the top 6 among all disciplines. Accordingly, the bibliometric map reveals that "toxicity" has become a hot keyword. It further reveals that the most common exposure types include acute, chronic, and combined exposure. The toxicological effects include behavioral, intestinal, cardiovascular, hepatic, endocrine toxicity, neurotoxicity, immunotoxicity, genotoxicity, and reproductive and transgenerational toxicity. The mechanisms include oxidative stress, inflammation, autophagy, and dysbiosis of gut microbiota. The toxicants commonly evaluated by using zebrafish model include nanomaterials, arsenic, metals, bisphenol, and dioxin. Overall, zebrafish provide a unique and well-accepted model to investigate the toxicological effects and mechanisms. We also discussed the possible ways to address some of the limitations of zebrafish model, such as the combination of human organoids to avoid species differences.