SCD1 negatively regulates autophagy-induced cell death in human hepatocellular carcinoma through inactivation of the AMPK signaling pathway.

Stearoyl-CoA desaturase 1 (SCD1) is a key regulator in the mechanisms of cell proliferation, survival and transformation to cancer, and autophagy also plays a critical role in hepatocellular carcinoma (HCC). However, whether SCD1 mediates autophagy in HCC remains unknown. In this study, we observed significantly elevated SCD1 expression levels and evident suppression of autophagy in HCC, and the positive SCD1 expression and autophagy defect were independently correlated with poor prognosis of HCC patients. We also found that the inhibition of SCD1 by a pharmacological inhibitor reduced cell viability and induced apoptosis and autophagy of human HCC cells in a dose- and time-dependent manner. Moreover, the pharmacological inhibition of AMPK supported the hypothesis that the induction of autophagy caused by SCD1 inhibition relied on AMPK stimulation. Furthermore, the human HCC cells death triggered by inhibition of SCD1 was partly involved in autophagy-induced apoptosis via AMPK signaling. Our findings reveal a novel role for SCD1 in the regulation of autophagy via AMPK signaling and provide mechanistic input for the clinical exploration that the combination of SCD1 inhibition with autophagy induction may be attractive for the management of HCC.