The Roles of Carcinoembryonic Antigen in Liver Metastasis and Therapeutic Approaches

Figure 2

Schematic representation of CEA-affecting biological events. Proteins indicated by the red letters are direct interacting molecules with CEA. Dotted arrows mean consequences of CEA-affecting biological events. In circulating colorectal cancer cells, DR5 (death receptor 5) and TBRI (TGF-β type I receptor) interact with CEA. Interaction with DR5 results in the inhibition of caspase-8 activity, inducing anoikis inhibition. Interaction with TBRI makes alteration of TGF-β signal pathways. Hence, cancer cells can abnormally overgrow. In Kupffer cells, hnRNP M4 interacts with CEA and secretes a series of cytokines such as IL-6, IL-10, and TNF-α. These cytokines can change liver microenvironments to a metastatic friendly environment for efficient metastasis of primary tumor cells. CEA also interacts with CEA antiparallelly and integrin. Interaction of CEA and integrin with CEA increases cell adhesion and distortion of cell architecture while inhibiting cell differentiation.