Research reportCathepsin L knockdown enhances curcumin-mediated inhibition of growth, migration, and invasion of glioma cells

•Curcumin treatment increased cathepsin L activity in glioma cells.•Cathepsin L knockdown could enhance the sensitivity of glioma cells to curcumin.•Inhibition of cathepsin L may be exploited in adjuvant clinical glioma therapy.

Curcumin can be used to prevent and treat cancer. However, its exact underlying molecular mechanisms remain poorly understood. Cathepsin L, a lysosomal cysteine protease, is overexpressed in several cancer types. This study aimed to determine the role of cathepsin L in curcumin-mediated inhibition of growth, migration, and invasion of glioma cells. Results revealed that the activity of cathepsin L was enhanced in curcumin-treated glioma cells. Cathepsin L knockdown induced by RNA interference significantly promoted curcumin-induced cytotoxicity, apoptosis, and cell cycle arrest. The knockdown also inhibited the migration and invasion of glioma cells. Our results suggested that the inhibition of cathepsin L can enhance the sensitivity of glioma cells to curcumin. Therefore, cathepsin L may be a new target to enhance the efficacy of curcumin against cancers.