KNSTRN knockdown impairs autophagy flux to inhibit bladder cancer progression.

Bladder cancer (BLCA) is a common malignant tumor of the urinary system. Kinetochore-localized astrin-binding protein (KNSTRN) has been implicated in the initiation and progression of multiple cancers. Furthermore, abnormal autophagy levels have been shown to significantly impact tumor development. However, the mechanism by which KNSTRN regulates autophagy in BLCA remains unclear. This study reveals that KNSTRN knockdown inhibits autophagy flux in BLCA. The mechanism involves ROS-dependent disruption of lysosomal function upon KNSTRN knockdown, thereby impeding autophagosome-lysosome fusion. Clioquinol restores lysosomal activity by regulating lysosomal pH, subsequently reestablishing autophagy flux. The ROS scavenger N-acetylcysteine (NAC) reverses lysosomal dysfunction and reactivates the autophagic flux. Furthermore, the autophagy activator rapamycin (Rapa) effectively counteracts KNSTRN knockdown-induced cell death in both in vitro and in vivo experiments. Collectively, we demonstrate that KNSTRN knockdown induces intracellular ROS accumulation and lysosomal dysfunction, thereby disrupting autophagic flux and inhibiting BLCA progression.