glucagon-like-peptide-1 and Adenocarcinoma

New-onset diabetes in pancreatic adenocarcinoma is due to a combination of insulin resistance and decreased β-cell function. Its differentiation from the common type 2 diabetes is the prerequisite for early diagnosis of pancreatic adenocarcinoma. Little attention has been paid to pancreatic stroma and surface proteases.. The activated fibroblasts selectively express fibroblast activation protein α, a structural homolog of the ubiquitously expressed dipeptidyl peptidase 4. Their role in pancreatic carcinogenesis is reviewed.. Homodimers and heterodimers of both enzymes display high specificity for peptides and proteins with penultimate proline or alanine. Most glucose-homeostatic agents are candidate substrates of these enzymes. The biological activity of truncated substrates is decreased or absent.. The interactions of surface proteases with glucose-homeostatic agents may adequately explain the evolution of diabetes associated with pancreatic adenocarcinoma and differentiate it from the common type 2 diabetes.

Topics: Adenocarcinoma; Diabetes Mellitus, Type 2; Dipeptidyl Peptidase 4; Early Diagnosis; Endopeptidases; Gelatinases; Glucagon-Like Peptide 1; Glucose; Humans; Insulin-Secreting Cells; Membrane Proteins; Pancreatic Neoplasms; Serine Endopeptidases

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.

Topics: Adenocarcinoma; Adult; Aged; Aged, 80 and over; Apoptosis; Carcinoma, Pancreatic Ductal; Cell Line, Tumor; Cell Movement; Cell Proliferation; Female; Gene Expression Regulation, Neoplastic; Glucagon-Like Peptide 1; Glucagon-Like Peptide-1 Receptor; Humans; Male; Middle Aged; Neoplasm Invasiveness; Signal Transduction

Despite interest in understanding glucagon-like peptide-1 (GLP-1) production, the factors important for GLP-1 biosynthesis remain poorly understood. We examined control of human proglucagon gene expression in NCI-H716 cells, a cell line that secretes GLP-1 in a regulated manner. Insulin, phorbol myristate acetate, or forskolin, known regulators of rodent proglucagon gene expression, had no effect, whereas sodium butyrate decreased levels of NCI-H716 proglucagon mRNA transcripts. The inhibitory effect of sodium butyrate was mimicked by trichostatin A but was not detected with sodium acetate or isobutyrate. The actions of butyrate were not diminished by the ERK1/2 inhibitor PD98059, p38 inhibitor SB203580, or soluble guanylate cyclase inhibitor LY83583 or following treatment of cells with KT5823, a selective inhibitor of cGMP-dependent protein kinase. NCI-H716 cells expressed multiple proglucagon gene transcription factors including isl-1, pax-6, pax-2, cdx-2/3, pax-4, hepatocyte nuclear factor (HNF)-3 alpha, HNF-3beta, HNF-3 gamma, and Nkx2.2. Nevertheless, the butyrate-dependent inhibition of proglucagon gene expression was not associated with coordinate changes in transcription factor expression and both the human and rat transfected proglucagon promoters were transcriptionally inactive in NCI-H716 cells. Hence, NCI-H716 cells may not be a physiologically optimal model for studies of human enteroendocrine proglucagon gene transcription.

Topics: Adenocarcinoma; Animals; Butyrates; Cecal Neoplasms; Gene Expression; Gene Expression Regulation; Glucagon; Glucagon-Like Peptide 1; Homeobox Protein Nkx-2.2; Homeodomain Proteins; Humans; Intestines; Nuclear Proteins; Peptide Fragments; Proglucagon; Protein Precursors; Rats; Transcription Factors; Tumor Cells, Cultured