miR-4461 inhibits liver cancer stem cells expansion and chemoresistance via regulating SIRT1.

MicroRNAs (miRNAs) were involved in tumorigenesis, progression, recurrence and drug resistance of hepatocellular carcinoma (HCC). However, few miRNAs have been identified and entered clinical practice. We show here that miR-4461 expression is reduced in liver cancer stem cells (CSCs) and predicts the poor prognosis of HCC patients. Knockdown of miR-4461 enhances the self-renewal and tumorigenicity of liver CSCs. Conversely, forced miR-4461 expression inhibits liver CSCs self-renewal and tumorigenesis. Mechanically, miR-4461 directly targets sirtuin 1 (SIRT1) via binding to its 3' untranslated region in liver CSCs. The correlation of miR-4461 and SIRT1 was confirmed in human HCC patients' tissues. Additionally, we found that miR-4461 overexpression hepatoma cells are more sensitive to cisplatin treatment. Patient-derived xenografts also showed that miR-4461 high HCC xenografts are sensitive to cisplatin treatment. Clinical cohort analysis further confirmed that HCC patients with high miR-4461 benefited more from transcatheter arterial chemoembolization treatment. In conclusion, our findings revealed the crucial role of miR-4461 in liver CSCs expansion and cisplatin response, rendering miR-4461 as an optimal target for the prevention and intervention of HCC.