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Biomedical subjects

Zihong Chen

Publications and source records attributed to Zihong Chen.

3 recordsLinked to original sources

Host metadherin coordinates hepatic lipid metabolism and CD8+ T cell immunity to promote tumor progression.

Cancer progression is systemically influenced by distant organ dysfunction induced by primary tumors, yet how long-distance tumor-organ crosstalk regulates antitumor immunity remains unclear. Here, we identify host metadherin (MTDH) as a critical regulator of tumor-induced immunosuppression and metabolic reprogramming via tumor-liver interactions. Using Mtdh knockout mouse models, we show that concurrent MTDH loss in hepatocytes and CD8+ T cells enhances effector T cell function and suppresses tumor growth and metastasis. Mechanistically, tumor-derived extracellular vesicles and particles (EVPs) activate Kupffer cells to secrete tumor necrosis factor α (TNF-α) and TGF-β, which suppress hepatic PPARα-mediated lipid oxidation via nuclear factor κB (NF-κB) signaling. MTDH loss restores hepatic lipid catabolism, reduces systemic lipid levels, and promotes mitochondrial metabolic reprogramming in CD8+ T cells under lipid-reduced conditions, thereby boosting antitumor immunity. Genetic or pharmacological targeting of MTDH synergizes with anti-PD-1 therapy. These findings establish host MTDH as a key mediator of tumor-liver crosstalk through metabolic and immune interactions, driving systemic cancer progression.

CD8(+) T cells

One-carbon unit supplementation fuels purine synthesis in tumor-infiltrating T cells and augments checkpoint blockade.

Nucleotides perform important metabolic functions, carrying energy and feeding nucleic acid synthesis. Here, we use isotope tracing-mass spectrometry to quantitate contributions to purine nucleotides from salvage versus de novo synthesis. We further explore the impact of augmenting a key precursor for purine synthesis, one-carbon (1C) units. We show that tumors and tumor-infiltrating T cells (relative to splenic or lymph node T cells) synthesize purines de novo. Shortage of 1C units for T cell purine synthesis is accordingly a potential bottleneck for anti-tumor immunity. Supplementing 1C units by infusing formate drives formate assimilation into purines in tumor-infiltrating T cells. Orally administered methanol functions as a formate pro-drug, with deuteration enabling kinetic control of formate production. Safe doses of methanol raise formate levels and augment anti-PD-1 checkpoint blockade in MC38 tumors, tripling durable regressions. Thus, 1C deficiency can gate antitumor immunity and this metabolic checkpoint can be overcome with pharmacological 1C supplementation.

Animals

One-carbon unit supplementation fuels tumor-infiltrating T cells and augments checkpoint blockade.

Nucleotides perform important metabolic functions, carrying energy and feeding nucleic acid synthesis. Here, we use isotope tracing-mass spectrometry to quantitate the contributions to purine nucleotides of salvage versus de novo synthesis. We further explore the impact of augmenting a key precursor for purine synthesis, one-carbon (1C) units. We show that tumors and tumor-infiltrating T cells (relative to splenic T cells) synthesize purines de novo. Purine synthesis requires two 1C units, which come from serine catabolism and circulating formate. Shortage of 1C units is a potential bottleneck for anti-tumor immunity. Elevating circulating formate drives its usage by tumor-infiltrating T cells. Orally administered methanol functions as a formate pro-drug, with deuteration enabling control of formate-production kinetics. In MC38 tumors, safe doses of methanol raise formate levels and augment anti-PD-1 checkpoint blockade, tripling durable regressions. Thus, 1C deficiency can gate antitumor immunity and this metabolic checkpoint can be overcome with pharmacological 1C supplementation.

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