Impact of cyclometalated ruthenium(II) complexes on lactate dehydrogenase activity and cytotoxicity in gastric and colon cancer cells.

Lactate dehydrogenase (LDH) is a redox enzyme often overexpressed in cancer cells allowing their survival in stressful metabolic tumor environment. Ruthenium(II) complexes have been shown to impact on the activity of purified horseradish peroxidase and glucose oxidase but the physiological relevance remains unclear. In this study we investigated how ruthenium complexes impact on the activity of LDH in vitro and in cancer cells and performed a comparative study using polypyridine ruthenium(II) complex [Ru(bpy)] (1) and its structurally related cyclometalated 2-phenylpyridinato counterpart [Ru(phpy)(bpy)] (2) (bpy=2,2'-bipyridine, phpyH=2-phenylpyridine).