Background:

IC50: 100 nM

RSL3 (1S,3R-) is the inhibitor of the glutathione peroxidase 4.

Maintaining cellular redox balance is critical for cell survival and tissue homoeostasis since imbalanced production of reactive oxygen species results in oxidative stress and cell death. The antioxidant enzyme glutathione peroxidase 4 is a important regulator of oxidative stress–induced cell death.

In vitro: RSL3, which was a glutathione peroxidase (GPX) 4 inhibitor, had been cooperated with the Smac mimetic BV6 to induce reactive oxygen species (ROS)-dependent cell death in acute lymphoblastic leukemia cells. It was found that addition of the caspase inhibitor failed to rescue ROS-induced cell death, suggesting that RSL3-induced cell death occured in a caspase-independent manner. Moreover, the iron chelator Deferoxamine inhibited RSL3/BV6-induced cell death significantly, however, it could not rescue cell death by Erastin/BV6, indicating that RSL3/BV6-, but not Erastin/BV6-mediated cell death depended on iron. In addition, it was shown that ROS production was required for both RSL3/BV6- and Erastin/BV6-induced cell death. In contrast, genetic or pharmacological inhibition of lipid peroxidation by GPX4 overexpression significantly decreased RSL3/BV6-induced cell death. Of importance, inhibition of lipid peroxidation could protect from RSL3/BV6-stimulated ROS production [1].

In vivo: Currently, there is no animal in vivo data reported.

Clinical trial: Up to now, RSL3 is still in the preclinical development stage.

Reference:
[1] Dchert J,Schoeneberger H,Rohde K,Fulda S.  RSL3 and Erastin differentially regulate redox signaling to promote Smac mimetic-induced cell death. Oncotarget.2016 Aug 29. doi: 10.18632/oncotarget.11687.