Biology of Human Tumors GSK-3b–Regulated N-Acetyltransferase 10 Is Involved in Colorectal Cancer Invasion

Purpose:NAT10 (N-acetyltransferase 10) is a nucleolar protein, butmay show subcellular redistribution in colorectal carcinoma. In this study,we evaluatedmembranous staining ofNAT10 in colorectal carcinoma and its clinical implications, and explored the mechanism of regulation of NAT10 redistribution. Experimental Design: The expression and subcellular redistribution of NAT10, b-catenin, E-cadherin, and GSK-3b were evaluated by immunohistochemistry in 222 cases of colorectal carcinoma. Regulation of NAT10 and its influence on cell motility were analyzed with inhibitors of GSK-3b, transfection of wild-type or kinase-inactivated GSK-3b, or expression of various domains of NAT10, and evaluated with immunofluorescence, Western blotting, and Transwell assays. Results: NAT10 localized mainly in the nucleoli of normal tissues, and was redistributed to the membrane in cancer cells, particularly at the invasive "leading edge" of the tumor. This correlated well with nuclear accumulation of b-catenin (P < 0.001; x 1⁄4 68.213). In addition, NAT10 membrane staining reflected the depth of invasion and tendency tometastasize (all P values < 0.001), and was associated with a poorer prognosis (P 1⁄4 0.023; x 1⁄4 5.161). Evaluation of the mechanism involved demonstrated that subcellular redistribution of NAT10 may result from its increased stability and nuclear export, which is brought about by inhibition of GSK-3b. Moreover, redistribution of NAT10 induces alteration of cytoskeletal dynamics and increases cancer cell motility. Conclusion:The subcellular redistributionofNAT10 canbe inducedbydecreases inGSK-3b activity. This redistribution increases cancer cell motility, and is, thus, correlated with invasive potential and poorer clinical outcome. This finding suggests that NAT10 may be a useful prognostic marker and potential therapeutic target in colorectal carcinoma. Clin Cancer Res; 20(17); 4717–29. 2014 AACR.