T125

Tumor markers play an important role in the identification of human malignancies. It has been shown that the carcinoembryonic antigen (CEA, CEACAM5) is a promoter of metastasis in epithelial cancers that is widely used as a clinical marker. The aim of this study is to elucidate the network of genes that are involved in the CEA-induced liver metastasis. Previously, we have shown that CEA is accumulated in the lungs and livers of rats by interacting with their macrophages. We identified and cloned a new gene (CEAR) for the CEA-binding protein, which is located on the surface of fixed liver macrophages, Kupffer cells (Bajenova et al, 2001). It has been shown that the interaction of CEA and CEAR proteins increases the production of IL-1, IL-10, IL-6, TNF-α cytokines (Thomas et al, 2011). This interaction changes the expression of liver adhesion molecules that enhances the survival of cancer cells to the liver. We also suggested that CEA synthesis by cancer cells may influence the E-cadherin adhesion junction complexes and have shown that CEA production violates the functional relationship between Ecadherin and its partners α-, β- and p120 catenin. A new type of interaction was discovered between the CEA and β-catenin and the increased amount of β-catenin in the nuclei of CEA producing cells. The data show that CEA production can cause the dissociation of cancer cells and trigger cancer progression. The CEA synthesis also alters splicing of p120 catenin protein and causes the release of soluble E-cadherin. Previously, CEA and epithelial E-cadherin were considered as independent tumor markers. Our data explain the correlation between the elevated levels of CEA and the increase in soluble E-cadherin in the progression of colorectal cancer (Bajenova et al, 2014).

We carried out a comparative transcriptome analysis of CEA-producing cell lines. The RNA transcriptome libraries were obtained and sequenced. By pairwise comparisons of CEA producing and non-producing cell lines using Cummerband program, we selected the set of genes (90 total genes) whose expression have been changed in the CEA-producing cell lines (overexpressed or downregulated). The biological processes that are linked to this differential gene expression were identified by Gene Set Enrichment Analysis (GSEA). In total, 8 significantly enriched GO terms related to the cellular components and biological processes were identified. Using KEGG and GO databases, we also identified the signaling pathways involved in the response to CEA. These findings have direct medical application, since they allow not only to establish the relationships between the existing biomarkers but also to discover the new ones. These biomarkers can be used for diagnosis and monitoring of metastatic carcinomas and for the drug development.