ClpX inhibition promotes ferroptosis through mitochondrial dysfunction to suppress pancreatic ductal adenocarcinoma progression

Caseinolytic protease X (ClpX) is an unfoldase that forms the ClpXP complex with caseinolytic protease P (ClpP), playing a critical role in maintaining mitochondrial protein homeostasis. While targeting ClpP has emerged as a promising cancer intervention strategy, the biological function of ClpX in cancer remains largely unexplored. In this study, we identify elevated expression of CLPX in pancreatic ductal adenocarcinoma (PDAC), which correlates with poor patient prognosis. CLPX knockdown significantly inhibits cell proliferation and disrupts mitochondrial protein homeostasis in PDAC cells. This knockdown also induces mitochondrial oxidative stress, impairs oxidative phosphorylation, and activates the unfolded protein response. CLPX knockdown increases reactive oxygen species (ROS) levels, ferrous ion accumulation, lipid peroxidation, and elevates malonaldehyde content, thus promoting ferroptosis. Furthermore, screening of reported ATPase inhibitors reveals that MSC1094308 binds to ClpX, inhibiting ClpXP-mediated substrate degradation. MSC1094308 induces unfolded protein stress and ferroptosis in PDAC cells. Altogether, our findings suggest that ClpX inhibition represents a potent therapeutic strategy for combating PDAC.