GPR12 inhibits migration and promotes apoptosis in esophageal cancer and hypopharyngeal cancer cells

BACKGROUND: G protein‐coupled receptor 12 (GPR12) is an orphan receptor with no confirmed endogenous ligands. It plays important roles in both physiological and pathological conditions such as neurogenesis and neural inflammation. However, it remains unclear whether GPR12 regulates carcinogenesis and progression in head and neck squamous cell carcinoma (HNSCC), such as esophageal cancer (EC) and hypopharyngeal cancer (HC). METHODS: The Cancer Genome Atlas (TCGA) database was applied to explore the expression of GPR12. Quantitative real‐time polymerase chain reaction (qRT‐PCR) was used to detect the expression of GPR12 in cancer tissues. Wound healing and transwell assays were carried out to verify the effect of GPR12 on cell migration. Flow cytometric analysis and caspase‐Glo 3/7 assay were carried out to verify the influence of GPR12 on cell apoptosis. Western blotting was used to measure the expression of proteins related to migration and apoptosis. RESULT: The qRT‐PCR analyses showed that the expression of GPR12 decreased in EC and HC than that in their paired adjacent normal tissues. Wound healing assay and transwell assay demonstrated that GPR12 inhibited tumor cell migration. Flow cytometry analysis and Caspase‐Glo 3/7 Assay suggested that GPR12 promoted apoptosis. The mechanism of GPR12 may function via modulating caspase‐7, E‐cadherin, and α‐catenin in EC and HC cells. CONCLUSION: In conclusion, GPR12 induced apoptosis by activating caspase‐7 and inhibited migration through epithelial‐to‐mesenchymal transition (EMT) in EC and HC. Our findings demonstrated that GPR12 as a potential tumor suppressor mediated cell migration and apoptosis in EC and HC.