Polarized Autologous Macrophages (PAM) Can Be a Tumor Vaccine

Abstract

Immunotherapy is currently recognized as one of the most promising anticancer strategies. In the tumor microenvironment, tumor-associated macrophages are mainly M2-type macrophages with tumor-promoting effects. Therefore, the reprogramming of tumor-associated macrophages from M2 to M1 type is a potential strategy for cancer therapy. We have previously shown the anticancer effects of implantable allogeneic M1 macrophages in mice. Here, we further engineered autologous mouse bone marrow cells into M1 macrophages and then embedded them into a sodium alginate gel to prepare an implantable immunotherapeutic agent (M1@Gel). We demonstrate that M1@Gel repolarizes M2 macrophages to M1 type and activates the immune responses in mice. As a result, M1@Gel can potently inhibit the tumor recurrence in mice after the surgical tumor removal. These results suggest that the implantation of autologous M1 macrophages might be a promising strategy for preventing postoperative tumor recurrence. We envisage that the employment of polarized autologous macrophages as a tumor vaccine might be translated into clinic.