EHD1 promotes the cancer stem cell (CSC)-like traits of glioma cells via interacting with CD44 and suppressing CD44 degradation

Plenty of evidence has shown that endocytosis plays a key role in Cancer progression; however, its effects in the progression of Cancer Stem Cells (CSCs) are still fragmentary. In the present study, we firstly identified that mammalian Eps15 homology domain protein 1 (EHD1), an endocytic and metastasis-associated gene, was upregulated in the 3D non-adherent spheres derived from glioma cells compared to that in the corresponding parental cells. Further functional experiments revealed that EHD1 knockdown reduced the CSC-like traits of glioma cells, which were evident by the decrease of sphere-formation ability, ALDH1 activity, and CSC markers' expression. Additionally, EHD1 knockdown attenuated the tumor-initiating ability of glioma cells in vivo. Furthermore, it was shown that EHD1 bound to CD44, enhanced CD44 stability, and prevented its total ubiquitination. Indeed, overexpression of CD44 rescued the inhibitory effects of EHD1 knockdown on the CSC-like traits of glioma cells. Finally, through the online dataset analysis, we found that EHD1 indeed exhibited a higher level in glioma tissues relative to that in normal tissues, and a positive correlation with CSC markers' expression in glioma tissues. Notably, EHD1 expression was negatively correlated with the overall survival and relapse-free survival of glioma patients. Thus, this work indicates that EHD1 might be a potent target for glioma progression, especially through breaking the EHD1-CD44 interaction.