Extracellular HMGB1 promotes CD44 expression in hepatocellular carcinoma via regulating miR-21

As a member of damage-associated molecular patterns (DAMPs), extracellular high-mobility group box 1 (HMGB1) plays a critical role in hepatocellular carcinoma (HCC) progression. Cluster differentiation 44 (CD44) has been demonstrated to participate in HCC progression. However, the relationship between extracellular HMGB1 and CD44 remains unclear. In this study, our results indicated that extracellular HMGB1 promoted the invasion, sphere formation and EMT process of HCC by increasing CD44 expression, which was dependent on miR-21. Moreover, miR-21 upregulated CD44 expression via activating OCT4/TGF-β1 signaling. Finally, we demonstrated the activation of Rage/JNK signaling caused by extracellular HMGB1 was responsible for miR-21 overexpression. Together, these findings reveal an important role of extracellular HMGB1 in HCC progression through upregulating miR-21/CD44.