LAPTM5 confers cisplatin resistance in NSCLC by suppressing LAMP1 ubiquitination to stabilize lysosomal membranes and sustain autophagic flux

Abstract

Cisplatin is a widely used chemotherapeutic agent in the treatment of non-small cell lung cancer (NSCLC), but cisplatin resistance remains a significant clinical challenge. Lysosomal transmembrane protein 5 (LAPTM5) is a lysosomal membrane protein implicated in macroautophagy/autophagy, although its precise mechanism has yet to be fully elucidated.In this study, we demonstrated that LAPTM5 promotes cisplatin resistance in NSCLC by maintaining lysosomal membrane stability and preserving autophagic flux. Mechanistic investigations showed that LAPTM5 competes with LAMP1 for binding to WWP2, thereby inhibiting LAMP1 ubiquitination and degradation, which ultimately preserves lysosomal membrane stability. LAPTM5 knockdown increases lysosomal membrane permeability, leading to the release of cathepsin D (CTSD), which elevates intracellular reactive oxygen species (ROS) levels; further destabilizing the lysosomal membrane and accelerating cell death. Our findings elucidate the mechanism by which LAPTM5 contributes to cisplatin resistance through lysosomal membrane stabilization and identify LAPTM5 as a potential therapeutic target for overcoming cisplatin resistance in NSCLC.