A new bis-pyrazolylpyridine ruthenium(III) complex as a potential anticancer drug: in vitro and in vivo activity in murine colon cancer

Antitumor studies evaluation of triphenylphosphine ruthenium complexes with 5,7-dihalo-substituted-8-quinolinoline targeting mitophagy pathways

Both ruthenium-containing complexes and 8-quinolinoline compounds have emerged as a potential novel agent for malignant tumor therapy. Here, three triphenylphosphine ruthenium complexes, [Ru(ZW1)(PPh3)2Cl2] (PPh3 = triphenylphosphine) (RuZ1), [Ru(ZW2)(PPh3)2Cl2] (RuZ2) and [Ru(ZW2)2(PPh3)Cl2]·CH2Cl2 (RuZ3) bearing 5,7-dichloro-8-quinolinol (H-ZW1) and 5,7-dichloro-8-hydroxyquinaldine (H-ZW2), have been synthesized, characterized and tested for their anticancer potential. We showed that triphenylphosphine ruthenium complexes RuZ1-RuZ3 impaired the cell viability of ovarian adenocarcinoma cisplatin-resistant SK-OV-3/DDP (SKO3CR) and SK-OV-3 (SKO3) cancer cells with greater selectivity and specificity than cisplatin. In addition, RuZ1-RuZ3 show higher excellent cytotoxicity than cisplatin towards SKO3CR cells, with IC50 values of 9.66 ± 1.08, 4.05 ± 0.67 and 7.18 ± 0.40 μM, respectively, in which the SKO3CR cells was the most sensitive to RuZ1-RuZ3. Depending on the substituent type, the antiproliferative ability of RuZ1-RuZ3 followed the trend: -CH3 > -H. However, RuZ1-RuZ3 have no obvious toxicity to normal cell HL-7702. Besides, RuZ1 and RuZ2 could induce mitophagy related-apoptosis pathways through suppression of mitochondrial membrane potential (ΔΨm), accumulation of [Ca2+] and reactive oxygen species (ROS), and regulation of LC3 II/LC3 I, Beclin-1, P62, FUNDC1, PINK1, Parkin, cleaved-caspase-3, caspase-9 and cytochrome c signaling pathway, and hindering the preparation of mitochondrial respiration complexes I and IV and ATP levels. Mechanistic study revealed that RuZ1 and RuZ2 induce apoptosis in SKO3CR cells via mitophagy related-apoptosis pathways induction and energy (ATP) generation disturbance. Taken together, the studied triphenylphosphine ruthenium complexes RuZ1-RuZ3 are promising chemotherapeutic agents with high effectiveness and low toxicity.

A comparative study of novel ruthenium(III) and iron(III) complexes containing uracil; docking and biological studies

Structural and biological studies were conducted on the novel complexes [Fe(U)2(H2O)2]Cl3 (FeU) and [Ru(U)2(H2O)2]Cl3 (RuU) (U = 5,6-Diamino-1,3-dimethylpyrimidine-2,4(1H,3H)-dione) to develop an anticancer drug candidate. The two complexes have been synthesized and characterized. Based on our findings, these complexes have octahedral geometry. The DNA-binding study proved that both complexes coordinated with CT-DNA. The docking study confirmed the potency of both complexes in downregulating the topoisomerase I protein through their high binding affinity. Biological studies have established that both complexes can act as potent anticancer agents against three cancer cell lines. RuU or FeU complexes induce apoptosis in breast cancer cells by increasing caspase9 protein and inhibiting proliferating cell nuclear antigen (PCNA) activity. In addition, both complexes down-regulate topoisomerase I expression in breast cancer cells. Therefore, the RuU and FeU complexes' anticancer activities were mediated via both apoptosis induction and topoisomerase I down-regulation. In conclusion, both complexes have dual anticancer activity pathways that may be responsible for the selective cytotoxicity of the complexes. This makes them more suitable for the development of novel cancer treatment strategies.

New Nanostructured Materials Based on Mesoporous Silica Loaded with Ru(II)/Ru(III) Complexes with Anticancer and Antimicrobial Properties

A new series of nanostructured materials was obtained by functionalization of SBA-15 mesoporous silica with Ru(II) and Ru(III) complexes bearing Schiff base ligands derived from salicylaldehyde and various amines (1,2-diaminocyclohexane, 1,2-phenylenediamine, ethylenediamine, 1,3-diamino-2-propanol, N,N-dimethylethylenediamine, 2-aminomethyl-pyridine, and 2-(2-aminoethyl)-pyridine). The incorporation of ruthenium complexes into the porous structure of SBA-15 and the structural, morphological, and textural features of the resulting nanostructured materials were investigated by FTIR, XPS, TG/DTA, zeta potential, SEM, and N₂ physisorption. The ruthenium complex-loaded SBA-15 silica samples were tested against A549 lung tumor cells and MRC-5 normal lung fibroblasts. A dose-dependent effect was observed, with the highest antitumoral efficiency being recorded for the material containing [Ru(Salen)(PPh₃)Cl] (50%/90% decrease in the A549 cells' viability at a concentration of 70 μg/mL/200 μg/mL after 24 h incubation). The other hybrid materials have also shown good cytotoxicity against cancer cells, depending on the ligand included in the ruthenium complex. The antibacterial assay revealed an inhibitory effect for all samples, the most active being those containing [Ru(Salen)(PPh₃)Cl], [Ru(Saldiam)(PPh₃)Cl], and [Ru(Salaepy)(PPh₃)Cl], especially against Staphylococcus aureus and Enterococcus faecalis Gram-positive strains. In conclusion, these nanostructured hybrid materials could represent valuable tools for the development of multi-pharmacologically active compounds with antiproliferative, antibacterial, and antibiofilm activity.

New ruthenium(II) complexes with quinone diimine and substituted bipyridine as inert ligands: synthesis, characterization, mechanism of action, DNA/HSA binding affinity and cytotoxic activity

This paper presents the synthesis and structural characterization of a series of new ruthenium(II) complexes 1-7, with the general formula mer-[RuL₃(N-N)Cl]Cl, where L is 2,2':6',2''-terpyridine (tpy) or 4'-(4-chlorophenyl)-2,2':6',2''-terpyridine (Cl-Ph-tpy) and N-N is o-benzoquinonediimine (o-bqdi), 2,3-naphthoquinonediimine (nqdi), 4,4'-dimethyl-2,2'-bipyridine (dmbpy) or 2,2'-bipyridine-4,4'-dicarboxylic acid (dcbpy). The kinetic results showed that the ligand substitution reactions of new Ru(II)-polypyridyl complexes with biomolecules were affected by different substituents and the aromaticity of meridional tridentate and bidentate spectator ligands as well as by the nature of the entering nucleophile. The reactivity of the complexes increases in the order: dmbpy < dcbipy < nqdi < o-bqdi. In addition, quantum chemical calculations were performed to support the interpretation and discussion of the experimental data. Furthermore, combining ethidium bromide (EB) and Hoechst 33258 (2-(4-hydroxyphenyl)-5-[5-(4-methylpiperazine-1-yl)benzimidazo-2-yl]-benzimidazole) fluorescence assay results implied that 1-7 might interact with calf thymus DNA through partial intercalation and/or minor groove binding. The human serum albumin (HAS)-fluorescence binding studies involving the site markers, eosin Y, as a marker for site I of subdomain IIA, and ibuprofen, as a marker for site II of subdomain IIIA, showed that Ru(II) compounds bind to both sites with moderately strong affinity (K_b = 10⁴-10⁶ M^-1). Moreover, these DNA/HSA experimental results were confirmed by molecular docking. Complexes 2, 5 and 6 exerted good to strong and highly selective cytotoxic activity against breast adenocarcinoma (MDA-MB 231), colorectal carcinoma (HCT116) and cervix adenocarcinoma (HeLa). Depending on their structure and cell line, the complexes acted differently in terms of their influence on autophagy, the cell cycle and the engaged apoptotic pathway.

Metal Coordination and Biological Screening of a Schiff Base Derived from 8-Hydroxyquinoline and Benzothiazole

Designing new metallodrugs for anticancer therapy is a driving force in the scientific community. Aiming to contribute to this field, we hereby report the development of a Schiff base (H2L) derived from the condensation of 2-carbaldehyde-8-hydroxyquinoline with 2-hydrazinobenzothiazole and its complexation with transition metal ions. All compounds were characterised by analytical and spectroscopic techniques, which disclosed their structure: [Cu(HL)Cl], [Cu(HL)2], [Ni(HL)(acetate)], [Ni(HL)2], [Ru(HL)Cl(DMSO)], [VO(HL)2] and [Fe(HL)2Cl(H2O)]. Different binding modes were proposed, showing the ligand’s coordination versatility. The ligand proton dissociation constants were determined, and the tested compounds showed high lipophilicity and light sensitivity. The stability of all complexes in aqueous media and their ability to bind to albumin were screened. Based on an antiproliferative in vitro screening, [Ni(HL)(acetate)] and [Ru(HL)Cl(DMSO)] were selected for further studies aiming to investigate their mechanisms of action and therapeutic potential towards colon cancer. The complexes displayed IC50 < 21 μM towards murine (CT-26) and human (HCT-116) colon cancer cell lines. Importantly, both complexes exhibited superior antiproliferative properties compared to the clinically approved 5-fluorouracil. [Ni(HL)(acetate)] induced cell cycle arrest in S phase in CT-26 cells. For [Ru(HL)Cl(DMSO)] this effect was observed in both colon cancer cell lines. Additionally, both compounds significantly inhibited cell migration particularly in the human colon cancer cell line, HCT-116. Overall, the therapeutic potential of both metal complexes was demonstrated.

Recent Advances in Photorelease Complexes for Therapeutic Applications”

Photorelease complexes represent a class of agents for which UV-visible light triggers the expulsion of a specfic molecule that is intrinsically part of the inner coordination sphere or held in...