CORM-3 induces DNA damage through Ru(II) binding to DNA

Abstract

When the “CO-releasing molecule-3”, CORM-3 (Ru(CO)3Cl(glycinate)) is dissolved in water it forms a range of ruthenium complexes. These are taken up by cells and bind to intracellular ligands, notably thiols such as cysteine and glutathione, where the Ru(II) reaches high intracellular concentrations. Here, we show that the Ru(II) ion also binds to DNA, at exposed guanosine N7 positions. It therefore has a similar cellular target to the anticancer drug cisplatin, but not identical, because Ru(II) shows no evidence of forming intramolecular crossbridges in the DNA. The reaction is slow, and with excess Ru, intermolecular DNA crossbridges are formed. Addition of CORM-3 to human colorectal cancer cells leads to strand breaks in the DNA, as assessed by the alkaline comet assay. DNA damage is inhibited by growth media containing amino acids, which bind to extracellular Ru and prevent its entry into cells. We conclude that the cytotoxicity of Ru(II) is different from that of platinum, making it a promising development target for cancer therapeutics.

High Glucose Increases DNA Damage and Elevates the Expression of Multiple DDR Genes

“…WGCNA followed by pathway enrichment analysis revealed an over-representation of DNA damage response pathways upon changing glucose levels. We also interestingly detected significant DNA damage as DNA double-strand breaks, single-strand breaks, alkali-labile sites, DNA-DNA/DNA-protein cross-linking, incomplete excision repair sites and oxidative base alterations using the alkaline comet assay [39][40][41][42] in cells cultured in HG, which explains the need for a strong DDR response to control this damage. While the dysfunction of DNA repair proteins through their loss or mutations has gathered significant research focus, factors driving the overexpression of DNA repair proteins, such as hyperglycemia, are not well understood.…”

“…To validate the bioinformatics results, we shifted to the wet lab and experimentally exposed MDA-MB-231 cells to LG after culturing in HG. To investigate the effects of highand low-glucose conditions on DNA damage, a comet assay was performed under alkaline conditions (pH > 13) to detect DNA double-strand breaks, single-strand breaks, alkalilabile sites, DNA-DNA/DNA-protein cross-linking, incomplete excision repair sites and oxidative base alterations [39][40][41][42]. Cells were cultured in high glucose and the comet tail moment was recorded.…”

Metal-based carbon monoxide releasing molecules with promising cytotoxic properties

“…It was verified that CORM-3 causes a significant increase in DNA strand breakage in poorly differentiated colon carcinoma RKO cells as evidenced by alkaline comet test. 130 A variety of challenges, including the instability of CORM-3 in water, short t 1/2 value (see paragraph 4.3) in human plasma, and limited cellular absorption, are impeding its clinical development. 36 Due to their instability, poor water solubility for CORM-2, lack of selectivity, and questionable reactivities to biomolecules, the clinical use of CORMs as therapeutic drugs is constrained.…”

On the Question of CO’s Ability to Induce HO-1 Expression in Cell Culture: A Comparative Study Using Different CO Sources

“…In numerous cases, these CORMs were used as the only source of CO and the observed activities of these CORMs were attributed to CO through deductive reasoning. However, recent years have seen a large number of reports (>25 papers, e.g., refs − ) showing very pronounced chemical reactivities and CO-independent biological activities of these CORMs, raising questions as to whether the observed biological activities can be attributed to CO. Readers are referred to a recent comprehensive review on this subject …”