Astrocyte elevated gene 1 (AEG-1) promotes anoikis resistance and metastasis by inducing autophagy in hepatocellular carcinoma

Astrocyte elevated gene 1 (AEG-1) is overexpressed in hepatocellular carcinoma (HCC) and is strongly associated with tumor metastasis. Anoikis resistance and autophagy may play an important role in the survival of circulating tumor cells. However, the relationship among AEG-1, anoikis resistance, autophagy, and metastasis in HCC is still not clear. The results of this study indicate that AEG-1 expression is increased in HCC cell lines grown in suspension culture. AEG-1 could enhance anoikis resistance to promote the survival of detached HCC cells. Moreover, the anoikis resistance appears to be partly dependent on autophagy. Regulating AEG-1 expression changed the autophagy levels to modulate anoikis resistance, likely acting via the protein kinase RNA-like ER kinase (PERK)-eIF2 alpha-ATF4-CHOP signaling axis. Finally, inhibiting autophagy by RNA interference prevented the AEG-1-promoted metastasis of HCC xenografts to the liver and lungs of nude mice. Taken together, AEG-1 is a key contributor to anoikis resistance and metastasis by inducing autophagy in vitro and in vivo, and it may be a potential target for therapeutic intervention in HCC.