ZKSCAN3 Facilitates Liver Metastasis of Colorectal Cancer Associated with CEA-expressing Tumor

Aim: Zinc finger with KRAB and SCAN domain 3 (ZKSCAN3) is overexpressed in invasive colorectal cancer (CRC) cells and regulates the expression of several genes favoring tumor progression, including vascular endothelial growth factor (VEGF) and integrin β4. We evaluated the association of ZKSCAN3 and colorectal cancer liver metastasis (CLM) to determine whether it is related to invasive signaling pathways.

Materials and methods: The ratios of expression by primary tumor to normal tissue and metastatic tumor to normal tissue were compared between ZKSCAN3-overexpressing and underexpressing primary tumor groups.

Results: In terms of CLM, the ZKSCAN3 overexpression was positively correlated with carcinoembryonic antigen (CEA), VEGF, and AKT expression. The protein-expression analysis showed that ZKSCAN-specific siRNA knockdown reduced CEA expression in LoVo and LS174T CRC cells. Matrigel invasion by ZKSCAN3-overexpressing HCT116 cells was increased when examined on CEA-coated filters compared with phosphate-buffered saline-treated controls. Additionally, matrix metalloproteinase 9 (MMP9) expression was greater in cells with reference allele (GG) than substitution allele (CC) for ZKSCAN3 rs733743 (p=0.032). ZKSCAN3 protein expression of the high serum CEA group was increased in hepatic metastatic tissue compared with the primary tumor tissue, while in the group with normal serum CEA it decreased or was similar. Reference ZKSCAN3 alleles were correlated with male dominance, a family history of malignancy, high serum CEA concentration and stage IV CRC in 450 patients with sporadic CRC. In conclusion, ZKSCAN3 appears to promote colorectal tumor progression and invasion. ZKSCAN3 may facilitate hepatic metastasis of CRC associated with CEA particularly in cases with CEA-producing tumor.