Abstract B049: Interplay between tumor metabolism, vasculature, and T-cell infiltration in anti-tumor immunity
Authors: Colombo Giorgia , Kang Jee Hye , Serganova Inna , Zappasodi Roberta 
Published: October 2024

Abstract
Several patients do not benefit from anti-cancer immunotherapies due to resistance for metabolic adaptation and fitness of tumor cells. Highly glycolytic tumor cells outcompete effector T cells for glucose in the tumor microenvironment (TME), impairing T cell function. High levels of lactate dehydrogenase (LDH) correlate with poor prognosis in cancer patients undergoing immunotherapies, inducing aberrant angiogenesis by activating HIF-1α and VEGF expression in endothelial cells (ECs), underscoring a biological interplay between tumor metabolism and neo-angiogenesis that can impact anti-tumor immunity. Main vasculature cells – ECs and pericytes (PCs) – may serve as antigen-presenting cells (APC), influencing T cell responses. While these findings point to a joint metabolic and immune regulation of the vasculature:T-cell crosstalk in the TME, we currently lack a precise understanding of the mechanisms linking tumor metabolism, aberrant angiogenesis, and anti-tumor T-cell responses, and how cell-based therapy may be influence by these factors. We have compared and contrasted vasculature and immune cells phenotypes by high-dimensional flow cytometry in established tumor models representing three major metabolic states by perturbing the two main cellular hubs for producing energy (aerobic glycolysis, by LDHA knock-down; oxidative phosphorylation, by depleting mitochondria as in Rho0 cells) compared to control tumors (NC). We functionally tested the impact of intratumor T cell recruitment according to these phenotypes, by adoptive cell transfer (ACT) therapy using T cells from donor mice immunized with matched-tumor injected i.v. in RAG2 KO mice bearing metabolically-defective tumor (KD or Rho0) and control tumor (NC) in contralateral mammary fat pad. We found that glycolysis-low tumors (LDH-A KD) show a better vasculature with reduced proportions of angiogenic activated PCs (cluster1: NG2+PDGFRbneg) and increased frequencies of “stabilizing” PCs (cluster 2: NG2negPDGFRb+, which counteract the formation of leaky vessels), compared to NC. However, KD tumors also display a reduction in MECA-79+ high endothelial venules. Moreover, LDHA-KD vs. NC tumors displayed ECs and cluster 2 PCs with greater expression of MHCI and decreased expression of FAS-L, and more EC expressing MHCII or PD-L1. In addition, the immune infiltrate of KD tumors is characterized by increased amounts of T effector cells and lower amounts of Gr1-low myeloid derived suppressor cells (MDSCs). The changes in vascularization phenotype have been confirmed in RAG2 KO mice bearing bilateral tumor variants model. ACT in these mice bearing bilateral 4T1-NC and -KD tumors resulted in greater biodistribution of T cells in the KD tumors, showing decreasing tumor growth. Vasculature features correspond to greater intratumor T-cell trafficking, indicating a mechanistic link between tumor glycolysis, aberrant angiogenesis, and T-cell exclusion. This would aim to elucidate the mechanisms through which these processes are connected for developing more efficacious T-cell-targeted therapies.
Citation Format: Giorgia Colombo, Jee Hye Kang, Inna Serganova, Roberta Zappasodi. Interplay between tumor metabolism, vasculature, and T-cell infiltration in anti-tumor immunity [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor Immunology and Immunotherapy; 2024 Oct 18-21; Boston, MA. Philadelphia (PA): AACR; Cancer Immunol Res 2024;12(10 Suppl):Abstract nr B049.