Ferroptosis response segregates small cell lung cancer (SCLC) neuroendocrine subtypes.

Loss of TP53 and RB1 in treatment-naive small cell lung cancer (SCLC) suggests selective pressure to inactivate cell death pathways prior to therapy. Yet, which of these pathways remain available in treatment-naive SCLC is unknown. Here, through systemic analysis of cell death pathway availability in treatment-naive SCLC, we identify non-neuroendocrine (NE) SCLC to be vulnerable to ferroptosis through subtype-specific lipidome remodeling. While NE SCLC is ferroptosis resistant, it acquires selective addiction to the TRX anti-oxidant pathway. In experimental settings of non-NE/NE intratumoral heterogeneity, non-NE or NE populations are selectively depleted by ferroptosis or TRX pathway inhibition, respectively. Preventing subtype plasticity observed under single pathway targeting, combined treatment kills established non-NE and NE tumors in xenografts, genetically engineered mouse models of SCLC and patient-derived cells, and identifies a patient subset with drastically improved overall survival. These findings reveal cell death pathway mining as a means to identify rational combination therapies for SCLC. The high degree of subtype plasticity in small cell lung cancer (SCLC) poses a therapeutic challenge. Here, the authors show that the non-neuroendocrine (non-NE) subtype of SCLC is sensitive to ferroptosis while the neuroendocrine (NE) subtype is vulnerable to TRX anti-oxidant pathway inhibition, and the combination of these two treatments in SCLC circumvents non-NE/NE subtype plasticity.