Stabilin-1 in Tumor-Associated Macrophages: A Potential Therapeutic Target in Cancer Immunotherapy

Stabilin-1 (STAB1) is a multifunctional scavenger receptor expressed by endothelial cells of the liver, spleen, lymph nodes, bone marrow and a subset of macrophages. STAB1 interacts with different ligands and modulates a wide range of functions including cell trafficking, endocytosis, homeostasis, angiogenesis, and tumor vascularization. The role of STAB1 in cancer progression and metastasis first became evident in Stab1 knockout (KO) mice, which developed smaller primary tumors and metastatic foci for some cancers. To date, various clinical cohorts and preclinical rodent studies have shown that STAB1 inhibition is associated with elevated anti-tumor T-cell responses. Moreover, human trials using anti-STAB1 antibody treatment indicate a shift towards immune activation and the potential to overcome cancer treatment resistance experienced with other immunotherapies. Although the role of STAB1 in cancer development and metastasis remains to be defined, STAB1 signaling in tumor-associated macrophages and downstream immune modulation are thought to be crucial mechanisms. Herein, we discuss the role of STAB1 in tumor-associated macrophages in relationship to disease progression and patient outcome.