Cholesterol-lowering Decreased mTOR Complex 2 Signaling and Enhanced Antitumor Immunity

SummaryCholesterol-lowering interventions are employed widely and safely to reduce risk of cardiovascular disease. Cholesterol may have complex and opposing effects on immunity. We lowered serum cholesterol to clinically relevant levels in mice and evaluated the final adaptive immune response. Mice treated with oral ezetimibe exhibited enhanced antitumor immunity against syngeneic cancers in a CD8+ lymphocyte-dependent manner, produced immunity that was transferrable through lymphocytes, and enhanced central CD8+ T cell memory. In both mice and patients undergoing prostatectomy, lowering serum cholesterol inhibited mTORC2 signaling in lymphocytes and increased infiltration of CD8+ lymphocytes into prostate tumors. Lymphocyte-specific mTORC2 knockout mice demonstrated enhanced CD8+ lymphocyte function and antitumor capacity. In a prospective clinical trial, cholesterol-lowering intervention prior to prostatectomy decreased the proliferation of normal prostate and low-grade adenocarcinomas. Here, we show that lowering serum cholesterol may be an effective strategy to decrease signaling through mTORC2 and enhance antitumor CD8+ T cell memory.