Anti-CD47 antibody synergizes with cisplatin against laryngeal cancer by enhancing phagocytic ability of macrophages.

Cisplatin is mainly used in late-stage or recurrent laryngeal cancer patients. However, the effect of the chemotherapy is limited due to cisplatin resistance. Therefore, we explored the synergized role of immunosuppressive mediator with cisplatin in laryngeal cancer. Cancer cells isolated from tissues of patients with laryngeal cancer were treated with cisplatin to screen the potential immunosuppressive mediator, whose synergized effects with cisplatin were explored both in vivo and in vitro. CD47 was selected for its high expression in cisplatin-treated laryngeal cancer cells. Blocking CD47 expression using its neutralizing antibody (aCD47) synergized with cisplatin to increase macrophage phagocytosis in a co-culture system of human epithelial type 2 (Hep-2) cancer cells with tumor-associated macrophages (TAMs). Moreover, aCD47 together with cisplatin prevented tumor growth by inhibiting proliferation of cancer cells and the secretion of proinflammatory cytokines, as well as by inducing the apoptosis of cancer cells and phagocytosis of TAMs in a Hep-2-implanted mouse tumor model. aCD47 synergized with cisplatin against laryngeal cancer by enhancing the phagocytic ability of TAMs, and the combined therapy of cisplatin and aCD47 might serve as a novel therapeutic strategy against laryngeal cancer.