NHS: a novel pharmacological inhibitor of the mitochondrial F 1 F o -ATPase which represses viability of cancerous cells

Background and purpose The mitochondrial enzyme F1 Fo -ATPsynthase is core to cellular homeostasis. Its function is compromised in acute pathologies such as ischemia, as well as in those caused by long-term acquired metabolic dysfunctions. This makes the F1 Fo -ATPsynthase an important target for therapeutic interventions in diseases such as cancer. Despite this, pharmacological tools to selectively inhibit the hydrolysis of ATP by the F1 Fo-ATPase without affecting its synthesis remain scarce. Here, we report the synthesis and in vitro characterization of the NH-Sulfoximine (NHS) that is the suxolfimine analogue of the compound BTB-06584 (BTB) which we characterized as F1 Fo-ATPase inhibitor. Experimental approach The chemical structure of BTB worked as template to gain the sulfoximine analogue NHS whose activity was assessed in human neuroblastoma SH-SY5Y cell line. In this we profiled ATP levels (i), cell viability (ii), and mitochondrial quality control mechanisms (iii) when it was given alone or in combination with either the glucose analogue 2-deoxyglucose (2-DG) or the chemotherapeutic agent etoposide (Eto). Key results NHS selectively blocks the consumption of ATP by mitochondria, independently of the F1 Fo -ATPase Inhibitory Factor 1 (IF1 ), leading to a subtle cytoxicity associated with the concomitant engagement of autophagy and impairment of cell viability. Conclusion and implications This study describes a new pharmacological inhibitor of the mitochondrial F1 Fo -ATPase that is able, by selectively blocking ATP hydrolysis, to perturb the bioenergetic homeostasis of cancer cells leading to a non-apoptotic type of cell death.