Computational Assessment of a Dual-Action Ru(II)-Based Complex: Photosensitizer in Photodynamic Therapy and Intercalating Agent for Inducing DNA Damage

A combined quantum-mechanical and classical molecular dynamics study of a recent Ru(II) complex with potential dual anticancer action is reported here. The main basis for the multiple action relies on the merocyanine ligand, whose electronic structure allows the drug to be able to absorb within the therapeutic window and in turn efficiently generate ¹O₂ for photodynamic therapy application and to intercalate within two nucleobases couples establishing reversible electrostatic interactions with DNA. TDDFT outcomes, which include the absorption spectrum, triplet states energy, and spin-orbit matrix elements, evidence that the photosensitizing activity is ensured by an MLCT state at around 660 nm, involving the merocyanine-based ligand, and by an efficient ISC from such state to triplet states with different characters. On the other hand, the MD exploration of all the possible intercalation sites within the dodecamer B-DNA evidences the ability of the complex to establish several electrostatic interactions with the nucleobases, thus potentially inducing DNA damage, though the simulation of the absorption spectra for models extracted by each MD trajectory shows that the photosensitizing properties of the complex remain unaltered. The computational results support that the anti-tumor effect may be related to multiple mechanisms of action.

2,2'-Bipyrimidine-based luminescent Ru(ii)/Ir(iii)-arene monometallic and homo- and hetero-bimetallic complexes for therapy against MDA-MB-468 and caco-2 cells

To unearth suitable complexes that are capable of inhibiting the growth of MDA-MB-468 and Caco-2 cells, 2,2'-bipyrimidine-based luminescent Ru(ii)/Ir(iii)-arene monometallic and homo- and hetero-bimetallic complexes were synthesized. The complex [(η⁶-p-cymene)(η⁵-Cp*)Ru^IIIr^IIICl₂(K²-N,N-bipyrimidine)](PF₆)₂ [LRuIr] exhibited the best potency in both cells along with good GSH stability and strong binding efficacy with the biomolecules. The apoptotic event occurred in MDA-MB-468 cancer cells via cell cycle arrest.

Ru(ii), Ir(iii), Re(i) and Rh(iii) based complexes as next generation anticancer metallopharmaceuticals

Several anticancer drugs such as cisplatin, and its analogues, epirubicin, and doxorubicin are well known for their anticancer activity but the therapeutic value of these drugs comes with certain side effects and they cannot distinguish between normal and cancer cells. Thus, a major challenge for researchers around the world is to develop an anticancer drug with the least toxicity and more target specificity. With the successful reporting of NAMI-A and KP1019, a new path has emerged in the anticancer field. Recently, several Ru(ii) complexes have been reported for their anticancer activity due to their enhanced cellular uptake and selectivity towards cancer cells. Apart from the Ru(ii) complexes, a large amount of research has been carried out with Ir(iii), Re(i), and Rh(iii) based complexes, which exhibited promising anticancer activity. The present review reports various Ru(ii), Ir(iii), Re(i), and Rh(iii) based complexes for their anticancer activity based on their cytotoxicity profiles, biological targets and mechanism of action.

Experimental and theoretical characterization of the strong effects on DNA stability caused by half-sandwich Ru(II) and Ir(III) bearing thiabendazole complexes

The synthesis and characterization of two half-sandwich complexes of Ru(II) and Ir(III) with thiabendazole as ancillary ligand and their DNA binding ability were investigated using experimental and computational methods. ¹H NMR and acid-base studies have shown that aquo-complexes are the reactive species. Kinetic studies show that both complexes bind covalently to DNA through the metal site and non covalently through the ancillary ligand. Thermal stability studies, viscosity, circular dichroism measurements and quantum chemical calculations have shown that the covalent binding causes breaking of the H-bonding between base pairs, bringing about DNA denaturation and compaction. Additionally, molecular dynamics (MD) simulations and quantum mechanics/molecular mechanics (QM/MM) calculations shed light into the binding features of the Ru(II) and Ir(III) complexes and their respective enantiomers toward double-helical DNA, highlighting the important role played by the NˆN ancillary ligand once the complexes are covalently linked to DNA. Moreover, metal quantification in the nucleus of SW480 colon adenocarcinoma cells were carried out by inductively coupled plasma-mass spectrometry (ICP-MS), both complexes are more internalized than cisplatin after 4 h of exposition. However, in spite of the dramatic changes in the helicity of the DNA secondary structure induced by these complexes and their nuclear localization, antiproliferative studies have revealed that both, Ru(II) and Ir(III) complexes, cannot be considered cytotoxic. This unexpected behavior can be justified by the fast formation of aquo-complexes, which may react with components of the cell culture medium or the cytoplasm compartment in such a way that they may become deactivated before reaching DNA.

Cu(ii)-TACN complexes selectively induce antitumor activity in HepG-2 cells via DNA damage and mitochondrial-ROS-mediated apoptosis

A novel 1,4,7-triazacyclononane derivative (btacn), and its related copper complexes, Cu(btacn)Cl₂ and [Cu(btacn)₂]·(ClO₄)₂, exhibit potent anti-proliferation activity towards HepG-2 and HeLa cells, but low cytotoxicity towards normal cell lines.

Novel tetranuclear ruthenium(II) arene complexes showing potent cytotoxic and antimetastatic activity as well as low toxicity in vivo

Ruthenium complexes have attracted a surge of interest as anticancer drug candidates because of their low toxicity, diversity in mode-of-actions and non-cross drug resistance with conventional platinum-based agents. Despite remarkable advances, only a limited number of ruthenium complexes have been demonstrated to kill cancer cells and suppress metastasis simultaneously. Here, two organometallic tetranuclear Ru(II) arene complexes (Ru-1 and Ru-2) have been synthesized and evaluated for their in vitro activity against a panel of human cancer cell lines, including a cisplatin-resistant human lung cancer A549 cell line. A superior cytotoxic activity of the ruthenium complexes compared to cisplatin across distinct cell lines was observed. Further examination of the mechanism indicated that anticancer activity was accomplished by inducing apoptosis in cancer cells. In addition, we found that such compounds exhibited promising antimetastatic activity and reduced the invasiveness of cancer cells. Importantly, choosing Ru-1 as a target compound, a significantly enhanced safety profile relative to cisplatin in animals was validated, suggesting that these complexes can be used as promising candidates for cancer therapy and deserve further investigation.

Binding of aluminium/cacodylate complexes with DNA and RNA. Experimental and “in silico”study

Mechanism of the interaction of a dinuclear aluminium/cacodylate complex with nucleic acids.