EIF2S2 transcriptionally upregulates HIF1α to promote gastric cancer progression via activating PI3K/AKT/mTOR pathway

Eukaryotic translation initiation factor 2 subunit beta (EIF2S2) is a protein that controls protein synthesis under various stress conditions and is abnormally expressed in several cancers. However, there is limited insight regarding the expression and molecular role of EIF2S2 in gastric cancer. In this study, we identified the overexpression of EIF2S2 in gastric cancer by immunohistochemical (IHC) staining and found a positive correlation between EIF2S2 expression and shorter overall survival and disease-free survival. Functionally, we revealed that EIF2S2 knockdown suppressed gastric cancer cell proliferation and migration, induced cell apoptosis, and caused G2 phase cell arrest. Additionally, EIF2S2 is essential for in vivo tumor formation. Mechanistically, we demonstrated that EIF2S2 transcriptionally regulated hypoxia induicible factor-1 alpha (HIF1α) expression by NRF1. The promoting role of EIF2S2 in malignant behaviors of gastric cancer cells depended on HIF1α expression. Furthermore, the PI3K/AKT/mTOR signaling was activated upon EIF2S2 overexpression in gastric cancer. Collectively, EIF2S2 exacerbates gastric cancer progression via targeting HIF1α, providing a fundamental basis for considering EIF2S2 as a potential therapeutic target for gastric cancer patients.