Oncogenic roles of GPR176 in breast cancer: a potential marker of aggressiveness and a potential target of gene therapy

BACKGROUND: Belonging to the G-protein coupled receptor 1 family, G protein-coupled receptor 176 (GPR176) is associated with the Gz/Gx G-protein subclass and is capable of decreasing cAMP production. METHODS: GPR176 expression was detected by qRT-PCR, bioinformatics analysis, Western blot and immunohistochemistry, and compared with clinicopathological characteristics of breast cancer. GPR176-related genes and pathways were subjected to bioinformatic analysis. We also explored the effects of GPR176 on the phenotypes of breast cancer cells. RESULTS: Lower expression of GPR176 mRNA was seen in breast cancer than in normal tissues, but the opposite pattern was found for its protein (p < 0.05). GPR176 mRNA was associated with female sex, low T staging, non-Her-2(+) subtypes, non-mutant p53 status in breast cancer (p < 0.05). GPR176 methylation was negatively correlated with its mRNA level and T staging in breast cancer, and was higher in breast cancer than normal tissues (p < 0.05). GPR176 protein expression was positively correlated with older age, small tumor size, and non-luminal-B subtype of breast cancers (p < 0.05). The differential genes of GPR176 were involved in receptor-ligand interaction, RNA maturation, and so forth (p < 0.05). GPR176-related genes were categorized into cell mobility, membrane structure, and so on (p < 0.05). GPR176 knockdown weakened the proliferation, glucose catabolism, anti-apoptosis, anti-pyroptosis, migration, invasion, and epithelial-mesenchymal transition of breast cancer cells. CONCLUSION: These results indicate that GPR176 might be involved in the tumorigenesis and subsequent progression of breast cancer by deteriorating aggressive phenotypes. It might be utilized as a potential biomarker to indicate the aggressive behaviors and poor prognosis of breast cancer and a potential target of genetic therapy.