Mechanistic Insight of Rhenium-Based Compounds as Anti-Cancer Agents

Rhenium-based cancer drugs seem to be alternative drug candidates for platinum-based drugs in the treatment of cancer. Rhenium based anticancer compounds have attracted several researchers due to their various properties and wide-ranging applications as prodrug, drug conjugates, targeted delivery, imaging and cancer killing capacities. An array of rhenium compounds displays promising cytotoxic and phototoxic properties towards cancer cells. Re-complexes with aromatic or heteroaromatic ligands like polypyridine complexes, octahedral and tris (hydroxymethyl) phosphine(THP) have prodrug properties which upon irradiation, exhibits cytotoxicity activities. PentylcarbanatoRe(I) diimine complexes, 2-(acetyloxy) benzoate Re(CO3), Re(CO3) pentylcarbonato complexes, [Re(CO)3(2-amino-4-phenyl amino-6-(2-pyridyl)-1,3,5-triazine)Cl] and Thiophene-2-carbohydrazide Re(V) complexes exhibits strong DNA binding activities. The 2-acetylpyridine-derived hydrazones Re(CO)3, Re(I) polypyridyl complexes and fac-[Re(CO)3(phen)] carboxy lato complexes were conjugated with aspirin reported as anti-inflammatory drugs. OxoRe(V) complexes with 3,3′-thiodipropanethiol tridentate ligands have been reported to inhibit the cathepsin B and K. Similar, Re-based complexes are synthesised using various ligands and that exhibit selectivity, controlled release and high efficacy potentials. However, still this research is at the preclinical studies. Re-based complexes have well-documented for antioxidant, drug delivery, selective anticancer activities, anti-inflammatory, DNA binding and damage inducing potential depending on the type ligand-Re complexes to contribute to cancer therapy. Thus, Re-compounds can be utilised in targeted therapies through coupling them with the biomolecules especially proteins and anticancer drugs. Among them, diselenium-rhenium complexes have selectivity and reduce the stress in the tumor environment to down regulate the breast cancer specific inflammatory cytokines to enhance the anticancer activity. Therefore, rhenium-based drugs are promising drugs candidate other than platinum-based drugs.

Keywords: Anti-inflammatory, Anti-oxidant, Cancer imaging, Cancer treatment, Cytotoxicity, Mitochondrial targeting, Molecular target, Photoreactive, Rhenium drugs, Targeted therapy.