Document resource
Background Neutrophils, which accumulate in various cancers, have important and complex roles within the tumor immune microenvironment (TIME), either pro-tumorigenic or anti-tumorigenic. We and others have recently shown that accumulation of anti-tumorigenic neutrophils in the TIME contributes functionally to immune based therapies response. However, mechanistic based strategies to modulate the function of tumor-associated neutrophil (TAN) to become anti-tumorigenic remains limited.Methods To better characterize TAN associated with favorable outcomes a glycolysis score was generated by analyzing scRNA-seq data of bone metastasis samples from publicly available databases (both mouse and patients) and our center. Preclinical breast, lung, colon, melanoma syngeneic immune competent cancer models were established, and in vivo treatment efficacy of MCT4 inhibitor (MCT4i) and/or PD-1 blockade was evaluated. Changes within the TIME of multiple mouse models after MCT4i and/or PD-1 blockade was characterized by multispectral flow cytometry and scRNA-seq. The functional role of highly glycolytic TANs was evaluated via ex vivo cell co-culture models.Results The glycolysis level of TANs was decreased in tumors responsive to immunmodulation including PD-1 blockade and anti-CD40 therapy. The TAN glycolysis score was associated with patient immunosuppressive TIME and poor survival. Based on scRNA-seq analysis and multispectral flow cytometry, we observed the abnormal up-regulated and high glycolytic activity of TANs within the TIME of multiple mouse cancers (melanoma, lung, breast, colon, gastric cancer). We found that neutrophils can be induced by tumor-derived factors to have increased glycolytic activity. These highly glycolytic TANs (TAN hg), have immunosuppressive function and inhibit CD8+ T cell anti-tumor response. By both scRNA-seq and flow cytometry analysis, we identified Monocarboxylate Transporter 4 (MCT4) to be specifically highly expressed by TANhgcompared to other cell components in the TIME of both mice and patients across cancer types. Mechanistically, we found MCT4-lactate axis is responsible for the immunosuppressive function of TANhg. Next, we found VB124 (selective MCT4i) triggered considerable tumor-delay in multiple preclinical tumor models (B16, LLC, MC38, CT26, 4T1), and improved the anti-tumor effector function of both T cells and tumor-associated myeloid cells. Moreover, MCT4 inhibition effectively overcame the treatment resistance of PD-1 blockade in 4T1 and LLC tumors. The elevated glycolytic activity in TANs across 17 distinct human cancer types was also underscored by scRNA-seq data.Conclusions Our study uncovers critical new insights into the metabolic heterogeneity of tumor-associated neutrophils (TANs) and demonstrates the therapeutic potential of targeting TAN metabolism through MCT4 inhibition as a promising strategy for cancer immunotherapy ( figure 1).Abstract 1199 Figure 1Graphical abstract. High-glycolytic tumor-associated neutrophils (TANs) mediate immunosuppression through the MCT4-lactate axis, whereas targeting MCT4 reprograms TAN glycolysis and overcomes resistance to cancer immunotherapy