LAUSR

Tumor cells alter the immune microenvironment to facilitate metastatic progression. Galectin-1 (Gal1) is a known modulator of tumor growth and progression in multiple cancer types including head and neck cancer (HNC). However, its contribution to the regulation of metastasis is poorly understood. Through this study we report a previously unknown role for Gal1 in modulating the STING pathway to regulate metastasis. The cGAS-STING pathway has paradoxical roles in cancer depending on the kinetics and strength of its induction, with chronic STING activation being linked to immune suppression and tumor progression while acute activation being associated with immune activation. However, little is known about the pathways that promote chronic STING activation. Using HNC and lung cancer models, we show that Gal-1 enhances STING protein stability, leading to sustained NF-κΒ activation and heightened chemokine-driven recruitment of myeloid derived suppressor cells (MDSCs). We show that Gal1-STING connection fosters the establishment of pre-metastatic niche through polymorphonuclear MDSCs (PMN-MDSCs), which modify the local lung microenvironment to support metastatic spread. Notably, RNA sequencing of MDSCs isolated from pre-metastatic lungs indicate the role of PMN-MDSCs in remodeling collagen and the extracellular matrix in the pre-metastatic compartment. Our findings reveal an unexpected role of STING activation in metastatic progression of HNC and lung cancer models and establish Gal1 as an endogenous positive regulator of STING. Citation Format: Dhanya K. Nambiar, Vignesh Vignesh Viswanathan, Hongbin Cao, Weiruo Zhang, Li Guan, Manish Chamoli, Brittany Holmes, Christina Kong, Rachel Hildebrand, Amanda Koong, Rie Eyben, Amato Giaccia, Lingyin Li, Edgar Engleman, Quynh Thu Le. Galectin-1 mediated chronic tumoral-STING activation promotes metastasisthrough MDSC recruitment [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 66.