Downregulation of HIGD1B induces mitochondria‐mediated apoptosis in gastric cancer cells by inactivating Akt and ERK pathways

Abstract Gastric cancer (GC) is one of the most common malignancies worldwide. Hypoxia‐inducible domain (HIGD) family members (e.g., HIGD1A) have been linked to tumor progression. However, the role of HIGD1B (another HIGD family member) in GC has yet to be fully understood. Based on data from TCGA_GC, GSE65801, and GSE65801 data sets, HIGD1B levels were evaluated in normal and GC tissues. Next, HIGD1B levels were validated by reverse transcription‐quantitative PCR and western blot analysis analyses. Meanwhile, patients with GC in the TCGA_GC cohort were grouped into high‐ and low‐HIGD1B level groups, and overall survival, functional enrichment, and immune infiltration were analyzed. Additionally, gain‐ and loss‐of‐function experiments were performed to determine the function of HIGD1B in GC cells. Compared to normal controls, HIGD1B mRNA levels were significantly elevated in GC tissues. Moreover, high HIGD1B levels may be an independent indicator of poor prognosis in patients with GC. Additionally, high HIGD1B levels were correlated with high stromal and ESTIMATE scores and elevated expression of immune checkpoints in patients with GC. Functional analyses showed that HIGD1B deficiency notably suppressed GC cell proliferation, migration, and invasion. Moreover, HIGD1B deficiency significantly induced mitochondria‐mediated apoptosis in GC cells by inactivating Akt and ERK pathways. Collectively, HIGD1B may predict the prognosis of patients with GC and may function as an oncogene in GC. These findings suggest that HIGD1B may serve as a prognostic biomarker and potential therapeutic target in GC.