Immunotherapy Inhibits Tumor Cholesterol Synthesis via the IFN-γ-ΙRF1-SREBF2 Axis

Tumor cells employ metabolic mechanisms to limit antitumor immunity and promote resistance to immunotherapy. However, how immunotherapy modulates tumor metabolism remains unclear. Here, we demonstrated that anti-PD-1 treatment regulated cholesterol biosynthesis in cancer cells through the effector cytokine interferon IFN-γ. Mechanistically, IFN-γ-induced IRF1 transcriptionally suppresses the expression of SREBF2, a master regulator of cholesterol synthesis. Reduced cholesterol content inhibited tumor growth and sensitized tumor cells to statins, drugs lowering cholesterol. Overall, our study reveals that IFN-γ-mediated inhibition of cholesterol biosynthesis in tumor cells is an important antitumor mechanism of immunotherapy.