Abstract B038: Establishing a screening platform to identify key signaling molecules regulating cold tumor formation through immune evasion and exclusion
Authors: Liao Yi-Ting , Chen Li-Mei , Lin Wen-Jye 
Published: November 2024

Abstract
Many trial data have shown that cancer immunotherapy can successfully induce long lasting anti-cancer immune responses and increased the survival rate of cancer patients. One of the key challenges facing cancer immunotherapy is the low response rate of cancer patients to immunotherapy, suggesting that these cancer patients may have acquired resistance toward immunotherapy before treatments. Therefore, there is an unmet need for identifying the underlying mechanisms that promote resistance. One important hypothesis is that immune-excluded tumors (so called cold tumors) that lack of functional T cells have been often found in cancer patients who cannot respond well to cancer immunotherapy. To address this, we have successfully established a preclinical model for cold lung tumors, conducted RNA-seq, performed hallmark gene set enrichment analysis (GSEA) on cold tumor cells sorted in vivo, and identified several candidates associated with epithelial-mesenchymal transition, Wnt signaling, type I and II interferon (IFN) signaling, and p53 signaling. We hypothesize that their roles may either promote or inhibit the formation of cold tumors. One of the molecular candidates we identified, a molecule designated as IRC001, represents a crucial proof of concept for our experimental tumor model. We have unveiled a novel role for IRC001 in enhancing anti-tumor immunity, leading to the transformation of cold tumors into hot tumors and facilitating swift tumor regression through pathways reliant on T cells and type I IFN signaling. Our mechanistic studies have shown that IRC001 can trigger type I IFN signaling by engaging STING/TBK-1/IRF3-dependent pathways. To delve deeper into the spatial and molecular distinctions in mouse tumors (± IRC001), we initiated a preliminary study utilizing 10x Genomics/Visium to examine the spatial variations between these tumor types. Significantly, our spatial transcriptomic analysis revealed consistent immune-excluded and immune-enriched characteristics compared to traditional RNA sequencing methods. We conducted an analysis of TCGA datasets (The Cancer Genome Atlas) and observed that elevated IRC001 expression is associated with improved prognosis in SKCM (Skin Cutaneous Melanoma). Furthermore, our bioinformatics analysis revealed that melanoma patients exhibiting heightened IRC001 expression displayed positive responses to immune checkpoint blockade therapies. Therefore, we believe that our experimental tumor model can provide vital insights into the cold tumor microenvironment, shaping future therapeutic strategies, and pinpointing molecular candidates that can assist in selecting patients for successful immunotherapy.
Citation Format: Yi-Ting Liao, Li-Mei Chen, Wen-Jye Lin. Establishing a screening platform to identify key signaling molecules regulating cold tumor formation through immune evasion and exclusion [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Tumor-body Interactions: The Roles of Micro- and Macroenvironment in Cancer; 2024 Nov 17-20; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(22_Suppl):Abstract nr B038.