glucagon-like-peptide-1 and Liver-Neoplasms

Incretins, glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP), are hormones secreted from small intestine accompanied with oral intake. We previously showed that transforming growth factor (TGF)-α stimulates the migration of hepatocellular carcinoma (HCC) cells via mitogen-activated protein (MAP) kinases, AKT and Rho-kinase. However, it remains to be elucidated whether incretins affect HCC cell functions. In the present study, therefore, we investigated whether incretins affect the migration of HCC cells using human HCC-derived HuH7 cells. GLP-1, but not GIP, reduced both TGF-α- and hepatocyte growth factor (HGF)-induced cell migration. IBMX, an inhibitor of cyclic nucleotide phosphodiesterase, enhanced the suppressive effect of GLP-1. GLP-1 attenuated the phosphorylation of stress-activated protein kinase/c-Jun N-terminal kinase (SAPK/JNK) by TGF-α and HGF. Our results strongly suggest that GLP-1 suppresses TGF-α- and HGF-induced migration of HCC cells through inhibiting the SAPK/JNK signaling pathway, and that the inhibition by GLP-1 is due to cAMP production.

Topics: Carcinoma, Hepatocellular; Cell Line, Tumor; Cell Movement; Cyclic AMP; Glucagon-Like Peptide 1; Hepatocyte Growth Factor; Humans; JNK Mitogen-Activated Protein Kinases; Liver Neoplasms; Mitogen-Activated Protein Kinases; Phosphorylation; Transforming Growth Factor alpha

Nonalcoholic fatty liver is characterized by the abnormal accumulation of triglycerides within hepatocytes, resulting in a steatotic liver. Glucagon-like peptide 1 and its analog exendin-4 can ameliorate certain aspects of this syndrome by inducing weight loss and reducing hepatic triglyceride accumulation, but it is unclear whether these effects result from the effects of glucagon-like peptide 1 on the pancreas, or from direct action on the liver. This study investigated the direct action and putative cellular mechanism of exendin-4 on steatotic hepatocytes in culture. Steatosis was induced in cultured HepG2 human hepatoma cells by incubation in media supplemented with 2 mM each of linoleic acid and oleic acid. Steatotic hepatocytes were then pre-incubated in the protein kinase A inhibitor H89 for 30 min, then treated with exendin-4 over a period of 24 h. Cell viability and triglyceride content were characterized by a TUNEL assay and AdipoRed staining, respectively. Our results showed that steatotic cells maintained high levels of intracellular triglycerides (80%) compared to lean controls (25%). Exendin-4 treatment caused a significant reduction in intracellular triglyceride content after 12 h that persisted through 24 h, while protein kinase A inhibitors abolished the effects of exendin-4. The results demonstrate the exendin-4 induces a partial reduction in triglycerides in steatotic hepatocytes within 12 h via the GLP-1 receptor-mediated activation of protein kinase A. Thus, the reduction in hepatocyte triglyceride accumulation is likely driven primarily by downregulation of lipogenesis and upregulation of β-oxidation of free fatty acids.

Topics: Carcinoma, Hepatocellular; Cell Survival; Cyclic AMP-Dependent Protein Kinases; Exenatide; Fatty Liver; Glucagon-Like Peptide 1; Hep G2 Cells; Hepatocytes; Humans; Isoquinolines; Linoleic Acid; Lipogenesis; Liver Neoplasms; Oleic Acid; Pancreas; Peptides; Sulfonamides; Triglycerides; Venoms

The "metabolic competition" for nutrients between cancer cells and the patient has emerged as an important research area. For pediatric oncology, it remains unclear whether the neuroendokrine regulation of appetite by gastrointestinal hormones such as ghrelin "eat", GLP-1 (glucagon-like peptide, "do not eat"), and PYY (peptide tyrosine-tyrosine, "do not eat") is influenced by tumor growth.. In a prospective randomized study, human hepatoblastoma (HB) and neuroblastoma (NB) cells (3 × 10(6)) were transplanted into the abdominal wall of immune-incompetent (nu/nu) rats (ethic committee approval: TVV43/11). Sham-operated animals received cell culture medium only. Tumor growth was allowed for 8 weeks. Then, all the animals underwent a 2-hour oGTT (oral glucose tolerance test) and were assessed for serum levels of glucose, insulin, ghrelin, GLP-1, and PYY. Finally, all tumor masses and adipose tissues were excised and calculated.. Total body weight (including tumor masses) differed for HB (329+31 g), but not for NB (358+22 g) compared with Sham (361+35 g). Subcutaneous adipose tissue was significantly decreased for both the tumor groups (HB=2.6 g, NB=2.1 g, and Sham=3.5 g). Only for NB, fasting glucose (3.4 + 0.6 mmol/L) and insulin (0.89+0.11 ng/mL) levels were significantly decreased compared with Sham (4.4+0.6 mmol/L; 1.19+0.36 ng/mL) only. During the oGTT (all data calculated as area under the curve, AUC) glucose levels were significantly increased for HB (104 ± 10) and NB (102 ± 13) compared with Sham (84 ± 3), but insulin levels remained similar for either group. Triglyceride levels were increased for HB (0.51 mmol/L) and especially NB (0.73 mmol/L) compared with Sham (0.34 mmol/L). Inflammatory parameters did not differ between the groups. Total ghrelin levels were significantly increased for NB (111 ± 10) and altered for HB (102 ± 15) compared with Sham (84 ± 8). Vice versa GLP-1 was statistically decreased in HB (92 ± 7) and NB (88 ± 12) compared with Sham (127 ± 13). Finally, PYY levels were nonsignificantly reduced for HB (117 ± 5) and NB (120 ± 4) compared with Sham (146 ± 12).

Topics: Animals; Biomarkers; Blood Glucose; Dipeptides; Ghrelin; Glucagon-Like Peptide 1; Glucose Tolerance Test; Hepatoblastoma; Homeostasis; Humans; Lipid Metabolism; Liver Neoplasms; Neoplasm Transplantation; Neuroblastoma; Prospective Studies; Random Allocation; Rats; Rats, Nude; Triglycerides

Animal models with defective glucagon action show hyperplasia of islet α-cells, however, the regulatory mechanisms underlying the proliferation of islet endocrine cells remain largely to be elucidated. The Gcggfp/gfp mice, which are homozygous for glucagon/green fluorescent protein knock-in allele (GCGKO), lack all proglucagon-derived peptides including glucagon and GLP-1. The present study was aimed to characterize pancreatic neuroendocrine tumors (panNETs), which develop in the GCGKO mice. At 15 months of age, macroscopic GFP-positive tumors were identified in the pancreas of all the GCGKO mice, but not in that of the control heterozygous mice. The tumor manifested several features that were consistent with pancreatic neuroendocrine tumors (panNETs), such as organoid structures with trabecular and cribriform patterns, and the expression of chromogranin A and synaptophysin. Dissemination of GFP-positive cells was observed in the liver and lungs in 100% and 95%, respectively, of 15-month-old GCGKO mice. To elucidate the regulatory mechanism for tumor growth, PanNET grafts were transplanted into subrenal capsules in GCGKO and control mice. Ki-67 positive cells were identified in panNET grafts transplanted to GCGKO mice 1 month after transplantation, but not in those to control mice. These results suggest that humoral factors or conditions specific to GCGKO mice, are involved in the proliferation of panNETs. Taken together, GCGKO mice are novel animal model for studying the development, pathogenesis, and metastasis panNETs.

Topics: Animals; Disease Models, Animal; Gene Expression Regulation, Neoplastic; Glucagon; Glucagon-Like Peptide 1; Green Fluorescent Proteins; Humans; Immunohistochemistry; Islets of Langerhans; Liver Neoplasms; Mice; Mice, Knockout; Mice, Transgenic; Microscopy, Confocal; Neuroendocrine Tumors; Pancreatic Neoplasms; Proglucagon; Reverse Transcriptase Polymerase Chain Reaction

Topics: Aged; Carcinoma, Hepatocellular; Glucagon-Like Peptide 1; Humans; Insulin; Liraglutide; Liver Cirrhosis; Liver Neoplasms; Male; Treatment Outcome

The influence of Glucagon-like peptide-1 (GLP-1) and Exendin-4 on development of intrahepatic cholangiocarcinoma (ICC) is evaluated in the study. In vitro tests, including acute toxicity test, cell colony formation assays, cells proliferation and apoptosis, transwell assay, were performed. An ICC in situ tumor animal model was established. Then, animals were randomly divided into four groups (n = 6): control, Exendin-4 treatment, oxaliplatin treatment and Exendin-4-oxaliplatin treatment. Animals in the Exendin-4 treatment and Exendin-4-oxaliplatin treatment groups received a subcutaneous injection of Exendin-4 (100 μg/kg/day) for 1 week, and then received oxaliplatin (10 mg/kg/week) by tail vein injection. Animals in the control group received PBS. Immunohistochemistry tests were used for PCNA, Ki67, Caspase 3 expression in tumor tissue. Results show that that, after incubation of human cholangiocarcinoma cell lines, HuCCTI and GLP-1, or HuCCTI and Exendin-4, colony formation number was sharply decreased. However, GLP-1, HuCCTI or Exendin-4 did not affect the colony of normal cells. Combination treatment with oxaliplatin and Exendin-4 can significantly inhibit tumor cells' proliferation and promote apoptosis. The combined effect is stronger than that of oxaliplatin or Exendin-4. Combination treatment with oxaliplatin and Exendin4 can significantly decrease Ki67 and PCNA proteins' expression in subcutaneous tumors of nude mice. The inhibitory effect of Combination treatment with oxaliplatin and Exendin4 is clearly stronger than that of oxaliplatin. In addition, Combination treatment with oxaliplatin and Exendin4 can significantly increase Caspase3 protein positive expression. In short, these results show that combination treatment with oxaliplatin and Exendin4 can inhibit tumor cells' proliferation, and promote apoptosis.

Topics: Animals; Apoptosis; Bile Duct Neoplasms; Bile Ducts, Intrahepatic; Caspase 3; Cell Line, Tumor; Cell Proliferation; Cholangiocarcinoma; Disease Models, Animal; Exenatide; Glucagon-Like Peptide 1; Humans; Ki-67 Antigen; Liver Neoplasms; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Organoplatinum Compounds; Oxaliplatin; Peptides; Proliferating Cell Nuclear Antigen; Toxicity Tests, Acute; Transplantation, Heterologous; Venoms

Glucagon-like peptides (GLP) 1 and 2 are hormones derived from the post-translational processing of proglucagon in the intestinal L cells that influence intestinal motility and small bowel growth, respectively. We describe a patient with a neuroendocrine tumor of unknown primary origin with peritoneal carcinomatosis and diffuse liver metastases, who presented with constipation and nocturnal itching for over 3 years. Small bowel follow-through showed decreased small intestinal motility and marked intestinal hypertrophy. Biopsies from mesenterial lymph nodes showed, histologically, a well-differentiated neuroendocrine tumor (G1), with positive immunostaining for chromogranin A, GLP-1, GLP-2 and polypeptide YY (PYY). Jejunal biopsy demonstrated marked intestinal mucosal hypertrophy. HPLC analysis combined with RIA of tumor and serum extracts revealed that the tumor was producing and releasing fasting levels of GLP-1 of 738+/-20.7 pg/ml (normal levels (nl) <100 pg/ml), GLP-2 of 3,150+/-9 pg/ml (nl <100 pg/ml) as well as PYY 550 pg/ml (nl <100 pg/ml). Octreotide administration decreased levels of GLP-1 and GLP-2 and reduced small intestinal transit time from 150 to 50 min. However, tumor growth was not inhibited by octreotide, interferon or dacarbazine therapy and the patient died 8 months later. This is the first case report demonstrating the overproduction of GLP-1, GLP-2 and PYY from an neuroendocrine tumor, in a patient with intestinal hypertrophy and delayed intestinal transit time.

Topics: Cell Division; Gastrointestinal Transit; Glucagon; Glucagon-Like Peptide 1; Glucagon-Like Peptide 2; Humans; Intestinal Mucosa; Intestine, Small; Jejunum; Liver Neoplasms; Male; Neoplasms, Unknown Primary; Neuroendocrine Tumors; Peptide Fragments; Peptides; Peritoneal Neoplasms; Protein Precursors