SIRT5-mediated FDX1 desuccinylation confers cuproptosis resistance in lung adenocarcinoma

Cuproptosis, a copper-dependent cell death process induced by excessive copper, represents an emerging therapeutic strategy in oncology. However, tumor-specific molecular pathways regulating this process remain poorly defined. Here, we demonstrate that copper levels are elevated in lung adenocarcinoma (LUAD), and LUAD cell lines exhibit increased resistance to cuproptosis. Mechanistically, elevated copper stress promotes the expression of the desuccinylase SIRT5 while reducing global succinylation in LUAD cells. Furthermore, we found that SIRT5 is a critical mediator of cuproptosis through the desuccinylation modification on ferredoxin1 (FDX1) protein at Lys84. This modification triggers TRIM8-mediated ubiquitination, leading to FDX1 proteasomal degradation and enhanced cuproptosis resistance. These results reveal the important role of SIRT5 in LUAD cuproptosis resistance. Notably, combining the SIRT5 inhibitor MC3482 with the cuproptosis inducer Elesclomol-Cu synergistically suppresses tumor growth in vivo, suggesting a promising therapeutic strategy. These findings elucidate mechanisms underlying cuproptosis resistance and propose a novel treatment approach for LUAD.