SPAG5: the upstream protein of Wnt and the target of curcumin to inhibit hepatocellular carcinoma?

AbstractBackground:Curcumin inhibits hepatocellular carcinoma (HCC) related Wnt pathway has been proved and sperm associated antigen 5 (SPAG5) has also been reported to work through Wnt. But there was no report about curcumin inhibiting Wnt by SPAG5 in HCC.Methods:We first confirm the expression of SPAG5 in tissues and cell lines. Then observe the effect of SPAG5 and the regulation of curcumin on SPAG5 and Wnt pathway proteins. Subsequently, knockdown SPAG5 and overexpression of SPAG5, and the effect of curcumin on the expression of SPAG5 and the Wnt pathway protein was observed.Results:The results showed that SPAG5 was highly expressed in cancer tissues. Compared with normal hepatocytes, the expression of SPAG5 in hepatoma cell lines increased significantly at both mRNA and protein levels. Curcumin inhibits the expression of SPAG5 in hepatoma cell lines and inhibits migration and promotes apoptosis. Curcumin inhibits the expression of SPAG5 and Cyclin D1 in overexpression SPAG5 cell lines, but the inhibition of curcumin on Cyclin D1 was weakened after SPAG5 was knockdown.Conclusions:We can infer preliminarily that SPAG5 may be the upstream regulatory protein of Wnt, notably, curcumin may inhibit Wnt by inhibiting SPAG5.