Significance of expression of glucagon-like peptide 1 receptor in pancreatic cancer

Glucagon-like peptide 1 (GLP-1) induces insulin secretion and proliferation of pancreatic β-cells, and inhibits their apoptosis through the GLP-1 receptor (GLP-1R), thus providing a foundation for using GLP-1-based therapies for the treatment of type 2 diabetes. However, doubts have emerged regarding the drug safety of these therapies. We investigated the potential role of GLP-1R in pancreatic ductal adenocarcinoma (PDAC). GLP-1R expression was semi-quantitatively evaluated by immunohistochemistry in 48 PDAC samples, and its correlations with clinicopathological features were investigated. CFPAC-1 cells were used for GLP-1R knockdown to evaluate its effects on cell proliferation, migration and invasion. GLP-1R expression was positive in 23 tumors and negative in 25 tumors. No correlations were found between GLP-1R expression status and clinicopathological characteristics. Furthermore, GLP-1R expression status did not affect the patient prognosis (P=0.74). The majority of lymph node metastases (11 of 15 samples examined; 73%) were positive for GLP-1R expression. Immunoreactivity for GLP-1R was also noted in sites of perineural and lymphovascular invasion. GLP-1R knockdown significantly reduced the proliferation, migration and invasion of CFPAC-1 cells (P<0.05). In conclusion, although GLP-1R is not an independent prognostic factor in PDAC patients, it appears to have some implications for PDAC metastatic ability.