NH-sulfoximine: A novel pharmacological inhibitor of the mitochondrial F1Fo-ATPase, which suppresses viability of cancerous cells

Abstract

Background and Purpose: The mitochondrial F1Fo-ATPsynthase is pivotal for cellular homeostasis. When respiration is perturbed, its mode of action everts becoming an F1Fo-ATPase and therefore consuming rather producing ATP. Such a reversion is an obvious target for pharmacological intervention to counteract pathologies. Despite this, tools to selectively inhibit the phases of ATP hydrolysis without affecting the production of ATP remain scarce. Here, we report on a newly synthesised chemical, the NH-sulfoximine (NHS), which achieves such a selectivity. Experimental Approach: The chemical structure of the F1Fo-ATPase inhibitor BTB-06584 was used as a template to synthesise NHS. We assessed its pharmacology in human neuroblastoma SH-SY5Y cells in which we profiled ATP levels, redox signalling, autophagy pathways and cellular viability. NHS was given alone or in combination with either the glucose analogue 2-deoxyglucose (2-DG) or the chemotherapeutic agent etoposide. Key Results: NHS selectively blocks the consumption of ATP by mitochondria leading a subtle cytotoxicity associated via the concomitant engagement of autophagy which impairs cell viability. NHS achieves such a function independently of the F1Fo-ATPase inhibitory factor 1 (IF1). Conclusion and Implications: The novel sulfoximine analogue of BTB-06584, NHS, acts as a selective pharmacological inhibitor of the mitochondrial F1Fo-ATPase. NHS, by blocking the hydrolysis of ATP perturbs the bioenergetic homoeostasis of cancer cells, leading to a non-apoptotic type of cell death.