Synthesis, RNA-sequence and evaluation of anticancer efficacy of ruthenium(II) polypyridyl complexes toward HepG2 cells

Ru(II)-based complexes containing 2-thiouracil derivatives suppress liver cancer stem cells by targeting NF-κB and Akt/mTOR signaling

Cancer stem cells (CSCs) are defined as a rare population of cancer cells related to tumor initiation and maintenance. These cells are primarily responsible for tumor growth, invasion, metastasis, recurrence, and resistance to chemotherapy. In this paper, we demonstrated the ability of Ru(II)-based complexes containing 2-thiouracil derivatives with the chemical formulas trans-[Ru(2TU)(PPh3)2(bipy)]PF6 (1) and trans-[Ru(6m2TU)(PPh3)2(bipy)]PF6 (2) (where 2TU = 2-thiouracil and 6m2TU = 6-methyl-2-thiouracil) to suppress liver CSCs by targeting NF-κB and Akt/mTOR signaling. Complexes 1 and 2 displayed potent cytotoxic effects on cancer cell lines and suppressed liver CSCs from HepG2 cells. Increased phosphatidylserine exposure, loss of mitochondrial transmembrane potential, increased PARP (Asp214) cleavage, DNA fragmentation, chromatin condensation and cytoplasmic shrinkage were detected in HepG2 cells treated with these complexes. Mechanistically, complexes 1 and 2 target NF-κB and Akt/mTOR signaling in HepG2 cells. Cell motility inhibition was also detected in HepG2 cells treated with these complexes. Complexes 1 and 2 also inhibited tumor progression in mice with HepG2 cell xenografts and exhibited tolerable systemic toxicity. Taken together, these results indicate that these complexes are new anti-HCC drug candidates that can suppress liver CSCs.

Complexes of Ruthenium(II) as Promising Dual-Active Agents against Cancer and Viral Infections

Poor responses to medical care and the failure of pharmacological treatment for many high-frequency diseases, such as cancer and viral infections, have been widely documented. In this context, numerous metal-based substances, including cisplatin, auranofin, various gold metallodrugs, and ruthenium complexes, are under study as possible anticancer and antiviral agents. The two Ru(III) and Ru(II) complexes, namely, BOLD-100 and RAPTA-C, are presently being studied in a clinical trial and preclinical studies evaluation, respectively, as anticancer agents. Interestingly, BOLD-100 has also recently demonstrated antiviral activity against SARS-CoV-2, which is the virus responsible for the COVID-19 pandemic. Over the last years, much effort has been dedicated to discovering new dual anticancer-antiviral agents. Ru-based complexes could be very suitable in this respect. Thus, this review focuses on the most recent studies regarding newly synthesized Ru(II) complexes for use as anticancer and/or antiviral agents.

EVALUATION OF THE POTENTIAL CYTOTOXICITY OF RUTHENIUM COMPLEX II AGAINST U-373 GLIOBLASTOMA CELLS

Objective: The potential of ruthenium complexes as anticancer agents has gained significant attention in the scientific community. The aim of this study was to investigate the effect of dithiocyanato-N-bis[8(diphenylphosphino)quinoline]ruthenium (II), [Ru(N-P)2(NCS)2] on the glioblastoma U-373 tumor cells and apoptosis. Methods: Ru(N-P)2(NCS)2] was synthesized and characterized using FTIR, and X-ray crystallography. The cytotoxic effects of [Ru(N-P)2(NCS)2] on glioblastoma U-373 tumor cells were evaluated using both the trypan blue assay and the activity of caspase-3 to detect apoptosis. A DPPH scavenging assay was used to evaluate the antioxidant activity. Results: The [Ru(N-P)2(NCS)2] complex effectively inhibited the glioblastoma U-373 tumor cells with an IC50 of ~ 23 µg/ml. Similar to the majority of chemotherapeutic agents that kill via the intrinsic pathway, [Ru(N-P)2(NCS)2] induces apoptosis, which was confirmed by the activation of caspase-3, and these effects were dose-dependent. Ruthenium has antioxidant properties, so ruthenium Complex II exhibits lower toxicity towards normal cells while effectively targeting and eliminating cancer cells. Conclusion: [Ru(N-P)2(NCS)2] is considered promising for researchers investigating putative biological activities, particularly antitumor and immune-related activity.

Developing a Ruthenium(III) Complex to Trigger Gasdermin E-Mediated Pyroptosis and an Immune Response Based on Decitabine and Liposomes: Targeting Inhibition of Gastric Tumor Growth and Metastasis

To develop next-generation metal drugs with high efficiency and low toxicity for targeting inhibition of gastric tumor growth and metastasis, we not only optimized a series of ruthenium (Ru, III) 2-hydroxy-1-naphthaldehyde thiosemicarbazone complexes to obtain a Ru(III) complex (4b) with remarkable cytotoxicity in vitro but also constructed a 4b-decitabine (DCT)/liposome (Lip) delivery system (4b-DCT-Lip). The in vivo results showed that 4b-DCT-Lip not only had a stronger capacity to inhibit gastric tumor growth and metastasis than 4b-DCT but also addressed the co-delivery problems of 4b-DCT and improved their targeting ability. Furthermore, we confirmed the mechanism of 4b-DCT/4b-DCT-Lip inhibiting the growth and metastasis of a gastric tumor. DCT-upregulated gasdermin E (GSDME) was cleaved by 4b-activated caspase-3 to afford GSDME-N terminal and then was aggregated to form nonselective pores on the cell membrane of a gastric tumor, thereby inducing pyroptosis and a pyroptosis-induced immune response.

Antiproliferative activity of ruthenium complex II against human cancer cell in vitro

Despite significant advancements in cancer treatment, there is a constant need for new and effective therapeutic options. One such potential weapon in the fight against cancer is ruthenium complex II. In this article, we synthesized, characterized, and studied the activity of dithiocyanato-N-bis[8-(diphenylphosphino)quinoline]ruthenium (II) [Ru(N-P)2(NCS)2] against MCF-7 human adenocarcinoma cells and the MRC-5 cell lines from fetal lung fibroblast-like cells as normal cells, as well as the mechanisms of action and selectivity. This study demonstrated that [Ru(N-P)2(NCS)2] has cytotoxic activity against MCF-7 with IC50 values of 7.56 µg/ml and cytotoxic activity against MRC-5 cell lines with IC50 values of 576.6 µg/ml. [Ru(N-P)2(NCS)2] showed more selective cytotoxic activity against MCF-7 cancer cell lines than MRC-5 normal cell lines. . This study demonstrated the potent apoptotic activity of ruthenium complex II by determining the activation of caspase-3, highlighting its potential as a therapeutic agent in cancer treatment. The [Ru(N-P)2(NCS)2] is considered promising for researchers investigating putative biological activities, particularly antitumor and immune-related activity.

Study of the biological activity of photoactive bipyridyl-Ru(II) complexes containing 1,3,5-triaza-7-phosphaadamantane (PTA)

The water-soluble ruthenium complex cis-[Ru(dcbpyH)₂(PTAH)₂]Cl₂·3H₂O (1) (dcbpy = 4,4'-dicarboxy-2,2'-bipyridine; PTA = 1,3,5-triaza-7-phosphaadamantane) has been synthesized and characterised by NMR, IR spectroscopy, elemental analysis, and single-crystal X-ray diffraction. The optical properties of 1 were studied, including photoactivation under visible light, as well as its biological properties, together with those of the previously published Ru complexes cis-[Ru(bpy)₂(PTA)₂]Cl₂ (2), trans-[Ru(bpy)₂(PTA)₂](CF₃SO₃)₂ (3) and cis-[Ru(bpy)₂(H₂O)(PTA)](CF₃SO₃)₂ (4) (bpy = 2,2'-bipyridine). Anticancer activities of the complexes against human lung (A549), cervical (HeLa) and prostate (PC3) carcinoma cells were evaluated under dark conditions and upon photoactivation with visible light. None of the complexes exhibited cytotoxic activity in the absence of light irradiation (IC₅₀ > 100 μM). However, after photoactivation, the cytotoxicity of complexes 1, 2 and 3 against the three cell lines markedly increased, resulting in IC₅₀ values between 25.3 μM and 9.3 μM. Notably, these complexes did not show toxicity against red blood cells. These findings show the potential of complexes 1, 2 and, particularly, 3 for selective and controlled cancer photochemotherapy. The reactivity of the Ru complexes against DNA under UV-Vis irradiation was studied by analysing plasmid mobility. Experimental data shows that 4 unfolds supercoiled DNA (SC DNA) both in the dark and under visible irradiation, while 1 and 3 are only active under light, being 2 inactive in either case. The unfolding activities of complexes 3 and 4 were dependent on the air present in the reaction. The measured intracellular levels of reactive oxygen species (ROS) upon irradiation with complexes 1, 2 and 3 suggest that their mechanism of action is related to oxidative stress.

Significant increase of anticancer efficacy in vitro and in vivo of liposome entrapped ruthenium(II) polypyridyl complexes

Two polypyridyl ruthenium(II) complexes [Ru(DIP)₂(BIP)](PF₆)₂ (DIP = 4,7-diphenyl-1,10-phenanthrolie, BIP = 2-(1,1'-biphenyl-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, Ru1) and [Ru(DIP)₂(CBIP)](PF₆)₂ (CBIP = 2-(4'-chloro-1,1'-biphenyl-4-yl)-1H-imidazo[4,5-f][1,10]phenanthroline, Ru2) were synthesized. The cytotoxic activities in vitro of Ru1, Ru2 toward B16, A549, HepG2, SGC-7901, HeLa, BEL-7402, non-cancer LO2 were investigated using MTT method (3-(4,5-dimethylthiazole)-2,5-diphenltetraazolium bromide). Unexpectedly, Ru1, Ru2 can't prevent these cancer cells proliferation. To improve the anti-cancer effect, we used liposomes to entrap the complexes Ru1, Ru2 to form Ru1lipo, Ru2lipo. As expectation, Ru1lipo and Ru2lipo exhibit high anti-cancer efficacy, especially, Ru1lipo (IC₅₀ 3.4 ± 0.1 μM), Ru2lipo (IC₅₀ 3.5 ± 0.1 μM) display strong ability to block the cell proliferation in SGC-7901. The cell colony, wound healing, and cell cycle distribution show that the complexes can validly inhibit the cell growth at G2/M phase. Apoptotic studied with Annex V/PI doubling method showed that Ru1lipo and Ru2lipo can effectively induce apoptosis. Reactive oxygen species (ROS), malondialdehyde, glutathione and GPX4 demonstrate that Ru1lipo and Ru2lipo improve ROS and malondialdehyde levels, inhibit generation of glutathione, and finally result in a ferroptosis. Ru1lipo and Ru2lipo interact on the lysosomes and mitochondria and damage mitochondrial dysfunction. Additionally, Ru1lipo and Ru2lipo increase intracellular Ca²⁺ concentration and induce autophagy. The RNA-sequence and molecular docking were performed, the expression of Bcl-2 family was investigated by Western blot analysis. Antitumor in vivo experiments confirm that 1.23 mg/kg, 2.46 mg/kg of Ru1lipo possesses a high inhibitory rate of 53.53% and 72.90% to prevent tumor growth, hematoxylin-eosin (H&E) results show that Ru1lipo doesn't cause chronic organ damage and strongly promotes the necrosis of solid tumor. Taken together, we conclude that Ru1lipo and Ru2lipo cause cell death through the following pathways: autophagy, ferroptosis, ROS-regulated mitochondrial dysfunction, and blocking the PI3K/AKT/mTOR.

Naphthalene Diimide-Functionalized Half-Sandwich Ru(II) Complexes as Mitochondria-Targeted Anticancer and Antimetastatic Agents

In this work, four naphthalene diimide (NDI)-functionalized half-sandwich Ru(II) complexes Ru1-Ru4 bearing the general formula [(η⁶-arene)Ru^II(N^N)Cl]PF₆, where arene = benzene (bn), p-cymene (p-cym), 1,3,5-trimethylbenzene (tmb), and hexamethylbenzene (hmb), have been synthesized and characterized. By introducing the NDI unit into the N,N-chelating ligand of these half-sandwich complexes, the poor luminescent half-sandwich complexes are endowed with excellent emission performance. Besides, modification on the arene ligand of arene-Ru(II) complexes can influence the electron density of the metal center, resulting in great changes in the kinetic properties, catalytic activities in the oxidative conversion of NADH to NAD⁺, and biological activities of these compounds. Particularly, Ru4 exhibits the highest reactivity and the strongest inhibitory activity against the growth of three tested cancer cell lines. Further study revealed that Ru4 can enter cells quickly in an energy-dependent manner and preferentially accumulate in the mitochondria of MDA-MB-231 cells, inducing cell apoptosis via reactive oxygen species overproduction and mitochondrial dysfunction. Significantly, Ru4 can effectively inhibit the cell migration and invasion. Overall, the complexation with NDI and modification on the arene ligand endowed the half-sandwich Ru(II) complexes with improved spectroscopic properties and anticancer activities, highlighting their potential applications for cancer treatment.