This study established a pyroptosis injury model by stimulating insulinoma cells(INS-1) of rats with high glucose(HG) and observed the impact of additional ethanol(ET) exposure on cell pyroptosis, as well as the intervention effect of salidroside(SAL). INS-1 cells were cultured and divided into a normal control group(NG), an HG group, an HG + ET(100 mmol·L~(-1)) group, and an HG + ET + SAL(1-100 μmol·L~(-1)) group. After 72 hours of treatment, cell viability was assessed using the cell counting kit-8(CCK-8) assay. The number of pyroptotic bodies was observed under a microscope. Western blot was used to detect changes in the intracellular Nod-like receptor protein 3(NLRP3)/gasdermin D(GSDMD) signaling pathway and adenosine monophosphate-activated protein kinase(AMPK) activity. A fluorescence probe was used to detect changes in intracellular reactive oxygen species(ROS) levels. Time-resolved fluorescence resonance energy transfer(TR-FRET) technology was employed to observe the effect of SAL on recombinant AMPK protein kinase activity in vitro. The results showed that compared to the NG group, HG exposure induced an increase in the number of pyroptotic bodies, elevated ROS levels, and activation of the NLRP3/GSDMD signaling pathway in INS-1 cells. Compared to the HG group, HG + ET exposure further exacerbated these changes. Compared to the HG + ET group, SAL dose-dependently increased cell viability, reduced the formation of pyroptotic bodies in INS-1 cells, and inhibited excessive ROS production, overactivation of the NLRP3/GSDMD signaling pathway, and the decrease in AMPK activity. TR-FRET experiments indicated that SAL could directly activate AMPK. When INS-1 cells were pretreated with an AMPK inhibitor, the effects of SAL on increasing cell viability, alleviating the formation of pyroptotic bodies, and inhibiting excessive ROS production were abolished. These results suggest that SAL can alleviate HG combined with ET-induced exacerbation of INS-1 pyroptosis by activating AMPK.
Pyroptosis/drug effects* ; Animals ; Rats ; Glucose/metabolism* ; Insulinoma/metabolism* ; Ethanol/pharmacology* ; Reactive Oxygen Species/metabolism* ; Glucosides/pharmacology* ; Phenols/pharmacology* ; Cell Line, Tumor ; Signal Transduction/drug effects* ; NLR Family, Pyrin Domain-Containing 3 Protein/genetics* ; Cell Survival/drug effects* ; AMP-Activated Protein Kinases/metabolism* ; Phosphate-Binding Proteins/genetics*

BACKGROUND: Emerging evidence suggests that sphingolipids may be involved in type 2 diabetes. However, the exact signaling defect through which disordered sphingolipid metabolism induces β-cell dysfunction remains unknown. The current study demonstrated that sphingosine-1-phosphate (S1P), the product of sphingosine kinase (SphK), is an essential factor for maintaining β-cell function and survival via regulation of mitochondrial action, as mediated by prohibitin (PHB). METHODS: We examined β-cell function and viability, as measured by mitochondrial function, in mouse insulinoma 6 (MIN6) cells in response to manipulation of cellular S1P and PHB levels. RESULTS: Lack of S1P induced by sphingosine kinase inhibitor (SphKi) treatment caused β-cell dysfunction and apoptosis, with repression of mitochondrial function shown by decreases in cellular adenosine triphosphate content, the oxygen consumption rate, the expression of oxidative phosphorylation complexes, the mitochondrial membrane potential, and the expression of key regulators of mitochondrial dynamics (mitochondrial dynamin-like GTPase [OPA1] and mitofusin 1 [MFN1]). Supplementation of S1P led to the recovery of mitochondrial function and greatly improved β-cell function and viability. Knockdown of SphK2 using small interfering RNA induced mitochondrial dysfunction, decreased glucose-stimulated insulin secretion (GSIS), and reduced the expression of PHB, an essential regulator of mitochondrial metabolism. PHB deficiency significantly reduced GSIS and induced mitochondrial dysfunction, and co-treatment with S1P did not reverse these trends. CONCLUSION: Altogether, these data suggest that S1P is an essential factor in the maintenance of β-cell function and survival through its regulation of mitochondrial action and PHB expression.
Adenosine Triphosphate ; Animals ; Apoptosis ; GTP Phosphohydrolases ; Insulin ; Insulin-Secreting Cells ; Insulinoma ; Membrane Potential, Mitochondrial ; Metabolism ; Mice ; Mitochondria ; Mitochondrial Dynamics ; Oxidative Phosphorylation ; Oxygen Consumption ; Phosphotransferases ; Repression, Psychology ; RNA, Small Interfering ; Sphingolipids ; Sphingosine

OBJECTIVETo investigate the expression of Yin Yang 1 (YY1) protein in human insulinoma and explore its clinical significance.

METHODSNineteen pancreatic neuroendocrine tumor tissue were collected from patients treated in Nanfang Hospital between 2000 and 2014. The protein expression of YY1 in benign and malignant insulinoma tissues were detected by immunohistochemistry.

RESULTSPositive expression for YY1 protein was detected in both benign and malignant tumor tissues, but the malignant tissues had a significantly greater intensity of YY1 expression than the benign tissues (P=0.042). The intensity of YY1 expression was positively correlated with the nature of the tumor, and the insulinomas with high expressions of YY1 had significantly greater malignant potentials (P=0.037).

CONCLUSIONThe high expression of YY1 protein is associated with the development of insulinima. YY1 may serve as a new tumor marker for detecting the malignant transformation of insulinoma.

Biomarkers, Tumor ; metabolism ; Cell Transformation, Neoplastic ; Humans ; Immunohistochemistry ; Insulinoma ; genetics ; metabolism ; Pancreatic Neoplasms ; genetics ; metabolism ; YY1 Transcription Factor ; genetics ; metabolism

Animals ; Carrier Proteins ; genetics ; metabolism ; Cell Line, Tumor ; Insulinoma ; genetics ; metabolism ; pathology ; Mice ; Neoplasm Proteins ; genetics ; metabolism ; Pancreatic Neoplasms ; genetics ; metabolism ; pathology ; Phosphoproteins ; genetics ; metabolism

No abstract available.
Biopsy ; Blood Glucose/metabolism ; C-Peptide/blood ; Calcium Gluconate/administration & dosage/*diagnostic use ; Female ; Humans ; Immunohistochemistry ; Injections, Intra-Arterial ; Insulin/blood ; Insulinoma/blood/*blood supply/pathology/surgery ; Middle Aged ; Pancreatic Neoplasms/blood/*blood supply/pathology/surgery ; Pancreaticoduodenectomy ; Splenic Artery/*radiography ; *Tomography, X-Ray Computed ; Treatment Outcome ; Tumor Markers, Biological/blood

Herein, we report the case of a large benign insulinoma in an obese young man with a three-year history of asymptomatic hypoglycaemia. He presented to our outpatient department with a two-week history of dizziness and morning cold sweats. A random serum glucose test revealed hypoglycaemia. Upon admission, computed tomography and magnetic resonance imaging of the abdomen with intravenous contrast media showed an enhancing mass lesion in the uncinate process of the pancreas. To confirm the diagnosis, an intra-arterial calcium stimulation test with hepatic venous sampling was performed for preoperative localisation and to exclude the presence of occult insulinomas. The patient underwent an exploratory laparotomy, with successful resection of the pancreatic head tumour. Histology confirmed the diagnosis of insulinoma. The patient's postoperative recovery was uneventful, and he has not developed further episodes of hypoglycaemia three years post surgery.
Adult ; Blood Glucose ; analysis ; Calcium ; metabolism ; Contrast Media ; chemistry ; Hepatic Veins ; pathology ; Humans ; Insulinoma ; blood ; complications ; diagnosis ; Magnetic Resonance Imaging ; Male ; Obesity ; blood ; complications ; Pancreatic Neoplasms ; blood ; complications ; diagnosis ; Tomography, X-Ray Computed

Multiple endocrine neoplasia type 1 (MEN1) is a dominantly inherited tumor syndrome characterized by development of various combinations of tumors in multiple endocrine glands, including the pituitary, parathyroid or pancreas. MEN1 results from mutations in tumor suppressor gene Men1, which encodes nuclear protein menin. Menin has been shown to preferentially repress cell proliferation in endocrine tissues including pancreatic beta cells. Herein, the present study was to explore the potential mechanisms underlying menin in repressing cell proliferation in mice MEN1 insulinoma. In the Gene Set Enrichment Analysis (GSEA), Ccnb2 (encoding cyclin B2) was up-regulated in pancreatic islets of Men1-excised mice after 14-day tamoxifen-feeding. Immunofluorescence with antibody against cyclin B2 revealed that the expression of cyclin B2 was greatly increased in MEN1 insulinoma. In Men1(-/-) cells, Men1 ablation leaded to an increase in cyclin B2 expression. Immunofluorescent staining by phospho-H3S10 antibody revealed the increasing number of Men1(-/-) cells in mitosis. Cells were seeded at a density of 5 × 10(4), then counted on day 2, 4 and 6, and the cell growth curve revealed Men1 ablation increased the cell proliferation. In contrast, knockdown of cyclin B2 by shRNA diminished the number of cells in mitosis and reduced cell proliferation. Further, chromatin immunoprecipitation (ChIP) assay indicated that menin affected the histone modification of the promoter of Ccnb2 by reducing the level of histone H3 lysine 4 tri-methylation (H3K4me3) and histone H3 acetylation but not affecting the level of histone H3 lysine 9 tri-methylation (H3K9me3) or histone H3 lysine 27 tri-methylation (H3K27me3). Our results suggest that menin may inhibit MEN1 insulinoma by suppressing cyclin B2 expression via histone modification.
Animals ; Cell Proliferation ; Cyclin B2 ; genetics ; metabolism ; Histones ; metabolism ; Insulinoma ; metabolism ; pathology ; Mice ; Mice, Knockout ; Multiple Endocrine Neoplasia Type 1 ; genetics ; Mutation ; Pancreatic Neoplasms ; metabolism ; pathology ; Proto-Oncogene Proteins ; genetics

BACKGROUNDIncreased levels of plasma lipopolysaccharide (LPS) have been found in obesity and diabetes patients. This study was to investigate the effect of LPS on pancreatic beta-cell viability and the involvement of caspase 3 in NIT-1 cell line.

METHODSMouse insulinoma NIT-1 cells were treated with LPS for the indicated time and dose. Cell viability was measured by cell counting kit-8 reagent. Toll-like receptor 4 (TLR4), caspase 3 and cleaved caspase 3 were detected by Western blotting. Insulin was determined by radioimmunoassay (RIA).

RESULTSLPS promoted NIT-1 cell proliferation at 1 µg/ml, peaked at 72 hours of incubation. A reduction in cleavage of caspase 3 was observed upon LPS treatment. Bay11-7082, a specific inhibitor of nuclear factor (NF)-κB, blunted LPS-induced inhibition of caspase 3 cleavage. Reduction in chronic insulin secretion was observed after treatment with LPS at 1 µg/ml for 48 and 72 hours, not for 24 hours. TLR4 protein was upregulated when NIT-1 cells were treated with LPS at 1 µg/ml for 24 hours.

CONCLUSIONSLPS promotes early NIT-1 cell proliferation in association with NF-κB-mediated inhibition of caspase 3 cleavage. LPS exerts a time-dependent inhibitory effect on chronic insulin secretion from NIT-1 cells.

Animals ; Caspase 3 ; metabolism ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Insulin ; secretion ; Insulinoma ; metabolism ; Lipopolysaccharides ; pharmacology ; Mice ; NF-kappa B ; metabolism ; Toll-Like Receptor 4 ; metabolism

OBJECTIVETo study of the role of nuclear transcription factor-κB (NF-κB) in high glucose-induced apoptosis in INS-1 cells.

METHODSRat insulinoma (INS-1) cells cultured in RPMI 1640 medium were treated with 11.1 mmol/L glucose, 33.3 mmol/L glucose, or 33.3 mmol/L glucose plus 5 µmol/L NF-κB inhibitors for 48 h. The expression of NF-κB subunit P65 protein in the cell nuclei was detected by Western blotting, IKK belta mRNA level by quantitative RT-PCR, and cell apoptosis by Annexin V-PI double staining.

RESULTSCompared with the control levels, IKK belta mRNA levels of the cells significantly increased in response to 33.3 mmol/L glucose exposure (P<0.01), which also resulted in significantly increased P65 protein expression in the cell nuclei (P<0.01) and cell apoptosis rate (P<0.05). Compared with those in the high glucose group, the expression of IKK belta mRNA and P65 protein and cell apoptosis rate decreased significantly after treatment with 33.3 mmol/L glucose plus 5 µmol/L NF-κB inhibitors (P<0.05).

CONCLUSIONHigh glucose induces NF-κB activation in INS-1 cells, and inhibition of NF-κB activation may protect INS-1 cells from high glucose-induced cell apoptosis.

Animals ; Apoptosis ; drug effects ; Cell Line, Tumor ; Gene Expression Regulation ; Glucose ; adverse effects ; metabolism ; Insulinoma ; pathology ; Pancreatic Neoplasms ; pathology ; Rats ; Transcription Factor RelA ; metabolism

OBJECTIVEResistin was thought to link the obesity to type 2 diabetes. This study aimed to investigate the effect of resistin on insulinoma cell proliferation.

METHODSpcDNA3.1-resistin was transfected into rat insulinoma cells RINm5F. Cell proliferation was assessed by the MTT assay. The resistin and SOCS3 mRNA levels were assessed by RT-PCR. The total Akt level and the phosphorylation status were assessed by Western blot.

RESULTSThe over-expressed resistin inhibited the RINm5F cell proliferation (p<0.05). SOCS-3 expression was up-regulated by resistin over-expression (3.2 folds over the control; p<0.05). Akt phosphorylation was down-regulated by resistin over-expression (0.6 fold over the control; p<0.05).

CONCLUSIONSResistin impairs the rat insulinoma cell RINm5F proliferation. This might be attributed to a down-regulation of Akt level caused by increased SOCS-3 expression.

Animals ; Cell Line, Tumor ; Cell Proliferation ; Insulinoma ; pathology ; Pancreatic Neoplasms ; pathology ; Phosphorylation ; Proto-Oncogene Proteins c-akt ; metabolism ; Rats ; Resistin ; genetics ; physiology ; Suppressor of Cytokine Signaling 3 Protein ; Suppressor of Cytokine Signaling Proteins ; genetics ; Transfection