Nanomaterials-involved strategies for reversing the immunosuppressive factors and improving antitumor immunotherapy

The past decade has witnessed the breakthrough of immunotherapy in the treatment of cancers. With the awakening of the autologous defense system, immunotherapy shows superior tumoricidal accuracy and recurrence/metastasis inhibition than any other antitumor therapies. However, the individualized therapeutic effects are usually restrained by the immunosuppressive tumor microenvironment (TME) of most tumors. For this challenge, lots of nanomaterials-involved strategies have been proposed to reverse the immunosuppressive factors and then improve the therapeutic effect and response rate of immunotherapy. Herein, we summarize the direct and indirect factors of immunosuppression in TME, and sum up the applications of nanomaterials-involved strategies in reversing immunosuppressive factors in TME. Furthermore, the current bottlenecks and prospects of nanomaterials-involved immune regulation strategies in antitumor immunotherapy are also discussed.