2-Phenylethynesulfonamide (PES) uncovers a necrotic process regulated by oxidative stress and p53

Abstract

2-Phenylethynesulfonamide (PES) or pifithrin-μ is a promising anticancer agent with preferential toxicity for cancer cells. The type of cell death and the molecular cascades activated by this compound are controversial. Here, we demonstrate PES elicits a caspase- and BAX/BAK-independent non-necroptotic necrotic cell death, since it is not inhibited by necrostatin-1. This process is characterized by an early generation of reactive oxygen species (ROS) resulting in p53 up-regulation. Accordingly, thiolic antioxidants protect cells from PES-induced death. Furthermore, inhibiting the natural sources of glutathione with l-buthionine-sulfoximine (BSO) strongly cooperates with PES in triggering cytotoxicity. Genetically modified p53-null or p53 knocked-down cells show resistance to PES-driven necrosis. The predominant localization of p53 in chromatin-enriched fractions added to the up-regulation of the p53-responsive gene p21, strongly suggest the involvement of a transcription-dependent p53 program. On the other hand, we report an augmented production of ROS in p53-positive cells that, added to the increased p53 content in response to PES-elicited ROS, suggests that p53 and ROS are mutually regulated in response to PES. In sum, p53 up-regulation by ROS triggers a positive feedback loop responsible of further increasing ROS production and reinforcing PES-driven non-necroptotic necrosis.

Keywords: 2-Phenylethynesulfonamide (PES); 2-Phenylethynesulfonamide (Pubmed CID 327653); 3-Methyladenine (Pubmed CID 1673); Anticancer drug; Dithiothreitol (Pubmed CID 19001); N-acetyl cysteine (Pubmed CID 12035); Necrosis; Necrostatin-1 (Pubmed CID 282833); Pifithrin-μ; Q-VD-OPh (Pubmed CID 11237609); Reactive oxygen species (ROS); l-Buthionine-sulfoximine (Pubmed CID 119565); p53.