Targeting CD47 Inhibits Tumor Development and Increases Phagocytosis in Oral Squamous Cell Carcinoma.

BACKGROUND Our previous work demonstrated upregulated CD47 in oral squamous cell carcinoma (OSCC). OBJECTIVE In the present study,we aimed to investigate the effects of CD47 on tumor cell development and phagocytosis in OSCC and elucidate the underlying mechanisms. METHODS The proliferation, apoptosis, migration, and invasion of oral cancer cells were analyzed after knocking down the expression of CD47. The effects of CD47 on tumor development were also evaluated using a murine model of OSCC. The involvement of CD47 in the phagocytosis of oral cancer cells was identified. RESULTS Cell proliferation was suppressed by knocking down the expression of CD47 in human OSCC cell line Cal-27 cells but there was no change in theapoptosis rate. Moreover, impaired expression of CD47 inhibited the migration and invasion of Cal-27 cells. Furthermore, we found that nude mice injected with CD47 knocked-down Cal-27 cells displayed decreased tumor volumes at week 9 compared to xenograft transplantations of blank Cal-27 cells. In addition, in vitrophagocytosis of Cal-27 cells by macrophages was significantly enhanced after the knockdown of CD47, which positively correlated with compromised STAT3/JAK2 signaling. CONCLUSION In summary, the knockdown of CD47 down regulated the development of OSCC and increased the phagocytosis of Cal-27 cells, indicating that CD47 might be a promising therapeutic target.