1-Methylnicotinamide is an immune regulatory metabolite in human ovarian cancer

Abstract

15Immune regulatory metabolites are key features of the tumor microenvironment (TME), yet with 16 a few notable exceptions, their identities remain largely unknown. We uncovered the immune 17 regulatory metabolic states and metabolomes of sorted tumor and stromal, CD4+, and CD8+ cells 18 from the tumor and ascites of patients with high-grade serous ovarian cancer (HGSC) using high- 19 dimensional flow cytometry and metabolomics supplemented with single cell RNA sequencing. 20 Flow cytometry revealed that tumor cells show a consistently greater uptake of glucose than T 21 cells, but similar mitochondrial activity. Cells within the ascites and tumor had pervasive 22 metabolite differences, with a striking enrichment in 1-methylnicotinamide (MNA) in T cells 23 infiltrating the tumor compared to ascites. Despite the elevated levels of MNA in T cells, the 24 expression of nicotinamide N-methyltransferase, the gene encoding the enzyme that catalyses the 25 transfer of a methyl group from S-adenosylmethionine to nicotinamide, was restricted to 26 fibroblasts and tumor cells. Treatment of T cells with MNA resulted in an increase in T cell-27 mediated secretion of the tumor promoting cytokine tumor necrosis factor alpha. Thus, the TME-28 derived metabolite MNA contributes to an alternative and non-cell autonomous mechanism of 29 immune modulation of T cells in HGSC. Collectively, uncovering the tumor-T cell metabolome 30 may reveal metabolic vulnerabilities that can be exploited using T cell-based immunotherapies to 31 treat human cancer. 32 Tumor-derived metabolites can have profound suppressive effects on anti-tumor immunity, with 33 increasing evidence that they can also function as key drivers of disease progression 1,2 . Beyond the 34 Warburg effect, recent work has begun to characterize the metabolic states of tumor cells and their 35 relationship to the immunological state of the TME. Studies in murine models have helped uncover the 36 role of metabolites such as (R)-2-hydroxyglutarate 3 , BH4 4 and methylglyoxal 5 as well as pathways 37 including glutamine metabolism 6 , oxidative metabolism 7 , and glucose metabolism 8 that impact T cell 38 function and antitumor immunity. Furthermore, studies in humans have elucidated key metabolic 39 pathways in tumors, for example demonstrating that tumors can use lactate as fuel 9 . Despite this, the 40 diversity and impact of specific metabolites on tumor-infiltrating lymphocytes (TILs) are largely 41 unknown. To characterize this diversity and better understand how metabolites in the TME influence T 42 cell function, a combined flow cytometry and mass-spectrometry approach was used to profile tumor 43 and TIL from patients with HGSC. Using this approach two spatially distinct microenvironments were 44 interrogated, the ascites 10 and tumor, within the same patients to reveal potential reciprocal metabolic 45 interactions between tumor cells and TIL. 47The phenotypic and metabolic states of cells in the matched ascites and tumor environments from six 48 patients ...

Cell Programmed Nutrient Partitioning in the Tumor Microenvironment

“…This work reveals that diverse cell populations can preferentially uptake different metabolites from a common pool in the TME in line with recent publications 38,39 . Previously, direct comparisons of in vivo glucose utilization between cancer cells and immune cells have not been reliably quantified 9,[40][41][42] .…”

Nicotinamide‐N‐methyltransferase is a promising metabolic drug target for primary and metastatic clear cell renal cell carcinoma

“…Notably, NNMT inhibition might not only inhibit cancer cells themselves but also impact the activation status of tumour‐infiltrating T cells through its reaction product 1‐MNA 51 . Along this line, the first data indicate that 1‐MNA treatment of pre‐stimulated T cells from healthy volunteers increases surface expression of the immune checkpoint PD1 on CD4+ and CD8+ T‐cell populations (Figure S11).…”

“…Regarding NNMT inhibition in cancer, one study showed decreased tumour burden and cancer cell proliferation in an orthotropic mouse model of ovarian cancer treated with an NNMT inhibitor 54 . In addition, a newly published study demonstrated the tumour‐promoting and immune‐suppressing effects of 1‐MNA, the NNMT‐dependent metabolite of nicotinamide, in ovarian cancer 51 . Kilgour et al.…”

Metabolic adaptation of lymphocytes in immunity and disease

“…Second, the metabolite 1-methylnicotinamine (MNA) that is likely derived from tumors accumulates in intratumoral T cells from patients with ovarian cancer. Moreover, MNA promotes TNF-a but reduces IFN-g production by T cells and limits their antitumor activity in vitro (Kilgour et al, 2021). Third, hepatocellular carcinoma cells produce high amounts of methionine metabolites that can promote Tex programming and impair antitumor responses (Hung et al, 2021).…”