Abstract PS03-02: Single-cell metabolic profiling uncovers new precision immunotherapy strategy in triple-negative breast cancer

Abstract Background: Immunotherapy has emerged as a novel cornerstone in the treatment of triple-negative breast cancer (TNBC), while its benefits have been observed in only a limited subset of patients. The intricate metabolic interplay between cancer cells and microenvironmental cells remodels the tumor microenvironment and exerts a significant influence on the responses to immunotherapy. However, there is still a lack of clarity regarding the strategies to target this metabolic crosstalk in order to predict efficacy and enhance sensitivity for immunotherapy. Methods: We conducted single-cell RNA sequencing (scRNA-seq) analysis on a cohort of 27 patients with TNBC receiving either immunotherapy combination regimen or chemotherapy alone. Building upon this foundation, we embarked on a comprehensive investigation of the single-cell metabolic landscape from three distinct perspectives: metabolic genes, metabolic pathways, and metabolic flux, represented by the flux balance analysis (FBA) algorithm Compass. Furthermore, we identified crucial cell subgroups that exhibited a strong correlation with immunotherapy efficacy and elucidated their metabolic characteristics to postulate potential metabolic crosstalk. Then, we employed the in vitro, in vivo, and patient-derived models to unravel the underlying mechanisms of metabolic crosstalk and proposed the translational strategies. Results: Utilizing newly-developed single-cell FBA method, we illustrated that different cell types have distinct metabolic features. Specifically, tumor cells and macrophages had more active metabolic reprogramming and higher metabolic heterogeneity. Furthermore, we illustrated that a subset of tumor cells having active antioxidant metabolism (featured by the upregulation of GSTP1) and macrophage subset depending on glutamine metabolism (characterized by CCL3+) were negatively and positively predictive of immunotherapy responses, respectively. Mechanistically, GSTP1-mediated excessive consumption of glutamine by tumor cells competitively restrained the intake of glutamine into CCL3+ macrophages to promote their ferroptosis and reduce their infiltration. Clinically, we demonstrated that targeting the GSTP1, which is specifically expressed in tumor cells, remodeled immune-metabolic microenvironment and enhanced immunotherapy efficacy. Furthermore, we established the utility of plasma CCL3 abundance, GSTP1 protein abundance, and CCL3 protein abundance, as robust predictors of response to immunotherapy, in several independent immunotherapy cohorts. Conclusion: Our study presented a comprehensive and multidimensional analysis of the single-cell metabolic landscape. Identifying the crucial metabolic crosstalk remodeling the immune microenvironment, our promising finding highlights the potential significance of modulating cell-cell metabolic interactions in sensitizing TNBC to immunotherapy, providing valuable insights for future therapeutic interventions. Citation Format: Ying Xu, Yi Xiao, Han Wang, Zhimin Shao, Yi-Zhou Jiang. Single-cell metabolic profiling uncovers new precision immunotherapy strategy in triple-negative breast cancer abstract. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PS03-02.