Abstract A023: Nicotinamide Phosphoribosyltransferase (NAMPT) is required for trained macrophage-mediated antitumor immunity

Abstract

Abstract Trained immunity or innate immune memory plays an active role in suppressing tumour growth and metastasis, however the specific metabolic mechanisms underlying such memory response-mediated antitumor activity have not been fully elucidated. Here, we show that the Nicotinamide Phosphoribosyltransferase/Nicotinamide Adenine Dinucleotide (NAMPT/NAD+) axis is required for the establishment of immune memory in macrophages against tumour. Chemical inhibition or genetic knockout of NAMPT in macrophages blocked trained immunity in vitro and in vivo, which could be rescued by NMN, an NAD+ precursor and a direct metabolite of NAMPT. Further studies revealed that myeloid-specific knockout of Nampt in mice significantly impaired the antitumor effect induced by in vivo β-glucan training, accompanied with decreased infiltration of intratumoral M1 macrophages. Interestingly, NAMPT deficiency did not impair β-glucan-induced interferon signalling or Akt/mTOR/HIF-1α signalling pathway, but markedly reduced histone methylation and acetylation levels, suggesting that NAMPT/NAD+ axis regulates trained immunity in macrophages via potential epigenetic mechanisms. Collectively, our study identifies that NAMPT/NAD+ metabolic axis-regulated trained immunity is a critical mechanism in early immune surveillance that suppresses tumour development via epigenetic regulation. Citation Format: Huan Jin, Yongxiang Liu, Xiaojun Xia. Nicotinamide Phosphoribosyltransferase (NAMPT) is required for trained macrophage-mediated antitumor immunity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2023 Oct 1-4; Toronto, Ontario, Canada. Philadelphia (PA): AACR; Cancer Immunol Res 2023;11(12 Suppl):Abstract nr A023.