GRP78 Promotes Hepatocellular Carcinoma proliferation by increasing FAT10 expression through the NF-κB pathway

Glucose-regulated protein 78(GRP78) and the ubiquitin-like protein FAT10 each promote proliferation in hepatocellular carcinoma(HCC). However, the relationship of GRP78 and FAT10 in HCC proliferation are still not known. In this study, we found that GRP78 and FAT10 were significantly overexpressed in HCC tissues compare with adjacent non-cancerous tissues, and a positive correlation was found between their expression and associated proliferation characteristics. High expression of GRP78 and FAT10 were positively correlated with tumor proliferation and poor prognosis in HCC. Moreover, GRP78 knockdown reduced FAT10 expression and suppressed HCC proliferation in vitro and in vivo. The effects of GRP78 knockdown were rescued by FAT10 up-regulation, whereas FAT10 knockdown reduced HCC proliferation enhanced by GRP78 up-regulation. Furthermore, GRP78 modulated FAT10 expression by regulating the NF-κB pathway, direct activation of the NF-κB pathway increased the expression of FAT10, a gene counteracting the tumor suppressor p53. Taken together, these results suggest that this newly identified GRP78-NF-κB-FAT10 axis will provide novel insight into the understanding of the regulatory mechanisms of proliferation in human HCC.