Abstract 2030: Inhibiting the GAS6/AXL axis suppresses tumor progression by blocking the interaction between cancer-associated fibroblasts and cancer cells in gastric carcinoma

Abstract

Cancer-associated fibroblasts (CAF) are a major component of tumor stroma and their effect on the progression of gastric carcinoma (GC) has recently been demonstrated. However, agents targeting the interaction between CAF and GC cells have not been applied in a clinical setting. The aim of this study was to investigate the effect of an AXL inhibitor on CAF-induced GC progression. We examined growth arrest specific factor 6 (GAS6) expression and phosphorylation of AXL in various cell lines, including GC cells and non-cancerous cells, by qPCR, western blot, and immunocytochemistry. We investigated the role of CAF-derived GAS6 on the migration and proliferation of GC cells using migration and cell survival assays. The effect of the AXL inhibitor, Bemcentinib, on the CAF-induced aggressive phenotype of GC cells was also investigated. Finally, we performed immunohistochemistry to measure the phosphorylation of AXL in a tissue microarray composed of 175 GC tissues, and evaluated its correlation with the prognosis of GC patients. qPCR and western blot analysis showed that GAS6 expression was higher in CAF relative to other cells. We found that CAF increased the phosphorylation of AXL (P-AXL), differentiation into a mesenchymal-like phenotype, and cell survival in GC cell lines. When the expression of AXL was inhibited in GC cells, the effect of CAF was reduced. In addition, Bemcentinib, a small molecule inhibitor of AXL, suppressed the effects of CAF on GC cell lines. In GC tissues, P-AXL positively correlated with the expression of vimentin (P < 0.001) and high levels of P-AXL were significantly associated with poor overall survival (P = 0.022).These findings suggest that CAF is a major source of GAS6 in the GC microenvironment and actively promotes an aggressive phenotype in GC cells through AXL activation. We conclude that an AXL inhibitor may be a novel agent for GC treatment. Citation Format: Dagyoeng Lee, Jongsu Woo, Cheong A Bae, In-Hye Ham, Hye Jung Oh, Sang-Yong Son, Sang-Uk Han, Tae-Min Kim, Jung Hwan Yoon, Won Sang Park, Hoon Hur. Inhibiting the GAS6/AXL axis suppresses tumor progression by blocking the interaction between cancer-associated fibroblasts and cancer cells in gastric carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2030.