SelenoResist · Targeting selenocysteine metabolism as a novel vulnerability in refractory non-small-cell lung cancer

IntroductionCoupled oxido-reductive (redox) reactions drive hydrogen peroxide fluctuations, mediating key cellular processes. Alterations in redox homeostasis support cancer cell survival and therapy resistance but simultaneously increase their reliance on antioxidant enzymes containing selenocysteine (Sec). Non-small cell lung cancer (NSCLC) is among the cancer types most highly dependent on available antioxidant capacity, and therapy-resistant NSCLC represents a vastly unmet clinical need. Inhibiting Sec metabolism is an underexplored anticancer strategy due to the complexity of the enzyme cascades and the challenges associated with selectively targeting their active sites. Since peroxiredoxin 6 (PRDX6) has a direct role in Sec metabolism and its loss selectively sensitizes resistant NSCLC cells to the oxidative stress cell death, ferroptosis, it represents an attractive target. ObjectivesThis project aims to develop and characterize the mechanisms of action of novel selective inhibitors of PRDX6 in resistant, persister and mesenchymal NSCLC cells. The compounds host a reactive element selective for the oxidized sulfenic acid form of cysteine, constituting a first-in-class selective covalent inhibitor with this target profile. Mechanistic studies will utilize functional proteomics to delineate the effects on selenoprotein homeostasis, cellular redox signaling pathways and cell cycle. The cell-based models for resistance, recurrence and metastatic NSCLC used here closely replicate the signaling cascades involved in patients on second- and third-line therapy. SignificanceSelenoResist combines the strengths of myself and my host laboratory to achieve a breakthrough in redox signaling research by developing a state-dependent PRDX6 inhibitor engaging only the oxidized form of its active site. This precision pharmacology tool will be leveraged to better understand selenium utilization pathways and break treatment resistance in lung cancer.