This study investigates the combination efficacy of EPHA3 monoclonal antibody and anti-CD47 antibody treatments in recurrent head and neck cancer through the reprogramming of TAMs (tumor-associated macrophages).

We utilized various cancer cell lines to assess the expression of EPHA3, CD47, and markers for M1 and M2 macrophage subtypes through western blotting, FACS, and FISH in both parent and radioresistant cell lines. The effects of EPHA3 and CD47 treatments were evaluated both in vitro and in vivo on human and mouse cell lines, with a focus on tumor growth, phagocytosis, and changes in immune cell infiltration

Our results indicated that overexpression of EPHA3 and CD47 is associated with decreased phagocytosis in radioresistant cancer cells, particularly within the M2 macrophage subset. However, combined treatment with EPHA3 and CD47 antibodies significantly reduced tumor growth and enhanced phagocytosis both in vitro and in vivo. This was accompanied by an increase in M1 macrophage markers (iNOS, TNF-α, IL-6) and a decrease in M2 markers (arginase 1, CD206, IL-10, P-STAT1), as demonstrated by flow cytometry. Additionally, EPHA3 antibody treatment was found to potentiate CD47-mediated repolarization towards the M1 phenotype. In conclusion, our findings suggest that treatment with EPHA3 and anti-CD47 antibodies promotes tumor cell phagocytosis and inhibits tumor growth by shifting TAMs from a tumor-promoting (M2) state to a tumor-inhibiting (M1) state in vivo

This highlights the potential therapeutic value of targeting TAM polarization in the treatment of recurrent head and neck cancer