Targeting the Cancer Biomarker CD47: A Review on the Diverse Mechanisms of the CD47 Pathway in Cancer Treatment

CD47 is a widely expressed cell membrane receptor belonging to the immunoglobulin (Ig) superfamily. CD47 is involved in a number of cellular processes, including proliferation, apoptosis, adhesion and migration through interacting with integrin, thrombospondins and SIRPα. CD47 also plays an important role in the immune system and homeostasis. In recent few years, numerous studies have demonstrated that targeting CD47 exhibits noticeable effects on inhibition of tumor growth and prevention of metastasis in various types of cancers, while the mechanisms is complicated. In this review, we stated three possible mechanisms of targeting CD47 for cancer treatment. First, blockade of CD47 interrupts the CD47-SIRPα pathway which helps cancer cells escape from phagocytosis by macrophages. Second, ligation of CD47 induces cancer cells apoptosis. Third, targeting CD47 improves the tumor microenvironment. We also described several prospective strategies that have been used for targeting CD47 in cancer therapy, including antibodies, miRNA/siRNA and recombinant protein, etc. In conclusion, CD47 is a promising cancer biomarker, and targeting CD47 presents an effective and potential therapeutic strategy through synthesized mechanisms.