CD47, which is also termed integrin-associated protein, is a 50-kDa cell surface glycoprotein that serves as an antiphagocytic molecule via binding to signal regulatory protein alpha (SIRPα), which is expressed on various phagocytic cells such as dendritic cells and macrophages. Thus, CD47 expression helps cells evade innate immunity. However, CD47 is broadly expressed on hematopoietic cells and other normal tissues, and the enhanced expression of CD47 has been reported on tumor cells in a variety of hematopoietic malignancies and solid tumors, such as leukemia, bladder cancer, astrocytoma, prostate cancer, and leiomyosarcoma. CD47 is known to have pleiotropic functions. For instance, CD47 monoclonal antibody induces caspase-independent leukemia cell death in chronic lymphocytic leukemia. In addition, CD47 stimulation induces cancer cell proliferation via a PI3K/Akt-dependent pathway in astrocytoma, and is also known to be associated with angiogenesis via vascular endothelial growth factor receptor-2. Thus, CD47 is associated with tumor progression, metastasis, and outcome, which suggests the recent cancer stem cell -based therapeutic potential of targeting CD47 in cancer.
Yoshida K, Tsujimoto H, Matsumura K, et al. CD47 is an adverse prognostic factor and a therapeutic target in gastric cancer. Cancer Medicine. 2015;4(9):1322-1333.
Liu J, Wang L, Zhao F, et al. Pre-Clinical Development of a Humanized Anti-CD47 Antibody with Anti-Cancer Therapeutic Potential. Bunting KD, ed. PLoS ONE. 2015;10(9):e0137345.