Metabolic oxidative stress elicited by the copper(II) complex Cu(isaepy)2 triggers apoptosis in SH-SY5Y cells through the induction of AMP-activated protein kinase/p38MAPK/p53 signalling axis Evidence for a combined use with 3-bromopyruvate in neuroblastoma treatment

摘要

We previously demonstrated that the complex bis[(2-oxindol-3-ylimino)-2-(2-aminoethyl)pyridine-N,N']copper(II), named [Cu(isaepy)2], induces AMPK-dependent/p53-mediated apoptosis in tumour cells by targeting mitochondria. Here, we reveal that p38MAPK is the molecular link of the phosphorylative cascade connecting AMPK to p53. Transfection of SH-SY5Y with a dominant negative mutant of AMPK results in apoptosis decrease, and a significant reduction of phospho-active p38MAPK and p53. Similarly, reverse genetics of p38MAPK yields a reduction of p53 and decreases apoptotic extent, confirming an exclusive hierarchy of activation that proceeds via AMPK/p38MAPK/p53. Fuel supplies counteract [Cu(isaepy)2]-induced apoptosis and AMPK/p38MAPK/p53 activation, with glucose being the most effective, suggesting a role for energetic dysbalance in [Cu(isaepy)2] toxicity. Co-administration of 3-bromopyruvate (3BrPA), a well-known inhibitor of glycolysis and succinate dehydrogenase, enhances apoptosis and AMPK/p38MAPK/p53 signalling pathway activation. Under these conditions, no toxic effect is observed in superoxide dismutase-overexpressing SH-SY5Y, or in primary cortical neurons (PCN), which are, conversely sensitized to the combined treatment with [Cu(isaepy)2] and 3BrPA only if grown in low glucose, or incubated with the glucose-6-phosphate dehydrogenase inhibitor, dehyroepiandrosterone. Overall, the results suggest that NADPH deriving from pentose phosphate pathway contributes to PCN resistance against [Cu(isaepy)2] toxicity and propose its employment in combination with 3BrPA as possible tool for cancer treatment.