Natural Products for the Immunotherapy of Glioma

Glioma immunotherapy has attracted increasing attention since the immune system plays a vital role in suppressing tumor growth. Immunotherapy strategies are already being tested in clinical trials, such as immune checkpoint inhibitors (ICIs), vaccines, chimeric antigen receptor T-cell (CAR-T cell) therapy, and virus therapy. However, the clinical application of these immunotherapies is limited due to their tremendous side effects and slight efficacy caused by glioma heterogeneity, antigen escape, and the presence of glioma immunosuppressive microenvironment (GIME). Natural products have emerged as a promising and safe strategy for glioma therapy since most of them possess excellent antitumor effects and immunoregulatory properties by reversing GIME. This review summarizes the status of current immunotherapy strategies for glioma, including their obstacles. Then we discuss the recent advancement of natural products for glioma immunotherapy. Additionally, perspectives on the challenges and opportunities of natural compounds for modulating the glioma microenvironment are also illustrated.