ICAM-1 promotes cancer progression by regulating SRC activity as an adapter protein in colorectal cancer

Colorectal cancer (CRC) has a 5-year survival rate of <10%, as it can metastasize to the lungs and liver. Anticancer drugs and targeted therapies used to treat metastatic colorectal cancer have insufficient therapeutic efficacy and are associated with complications. Therefore, research to develop new targeted therapeutics is necessary. Here, we present a novel discovery that intracellular adhesion molecule-1 (ICAM-1) is a potential therapeutic target to enhance therapeutic effectiveness for CRC. ICAM-1 is an important regulator of cell–cell interactions and recent studies have shown that it promotes malignancy in several carcinomas. However, little is known about its effect on CRC. Therefore, we conducted a study to define the mechanism by which ICAM-1 acts. ICAM-1 is phosphorylated by tyrosine-protein kinase Met (c-MET), and phosphorylated ICAM-1 can interact with SRC to increase SRC activity. Consequently, ICAM-1 may further accelerate SRC signaling, promoting the malignant potential of cancer. In addition, treatment with antibodies targeting ICAM-1 showed excellent therapeutic effects in reducing metastasis and angiogenesis. These findings suggest for the first time that ICAM-1 is an important adapter protein capable of mediating the c-MET-SRC signaling axis. Therefore, ICAM-1 can be used as a novel therapeutic target and a metastatic marker for CRC.