T-helper-1-cell cytokines drive cancer into senescence.

Cancer control by adaptive immunity involves a number of defined death and clearance mechanisms. However, efficient inhibition of exponential cancer growth by T cells and interferon-γ (IFN-γ) requires additional undefined mechanisms that arrest cancer cell proliferation. Here we show that the combined action of the T-helper-1-cell cytokines IFN-γ and tumour necrosis factor (TNF) directly induces permanent growth arrest in cancers.

Protein kinase C delta (PKCδ) affects proliferation of insulin-secreting cells by promoting nuclear extrusion of the cell cycle inhibitor p21Cip1/WAF1.

Background: High fat diet-induced hyperglycemia and palmitate-stimulated apoptosis was prevented by specific inhibition of protein kinase C delta (PKCδ) in β-cells. To understand the role of PKCδ in more detail the impact of changes in PKCδ activity on proliferation and survival of insulin-secreting cells was analyzed under stress-free conditions.

Methodology And Principal Findings: Using genetic and pharmacological approaches, the effect of reduced and increased PKCδ activity on proliferation, apoptosis and cell cycle regulation of insulin secreting cells was examined.

Fenamates as TRP channel blockers: mefenamic acid selectively blocks TRPM3.

Background And Purpose: Fenamates are N-phenyl-substituted anthranilic acid derivatives clinically used as non-steroid anti-inflammatory drugs in pain treatment. Reports describing fenamates as tools to interfere with cellular volume regulation attracted our attention based on our interest in the role of the volume-modulated transient receptor potential (TRP) channels TRPM3 and TRPV4.

Experimental Approach: Firstly, we measured the blocking potencies and selectivities of fenamates on TRPM3 and TRPV4 as well as TRPC6 and TRPM2 by Ca(2+) imaging in the heterologous HEK293 cell system.

The impact of genetic variation in the G6PC2 gene on insulin secretion depends on glycemia.

Context: Single-nucleotide polymorphisms (SNPs) within the G6PC2 locus are associated with fasting glucose and insulin secretion. These SNPs are not associated with type 2 diabetes risk.

Objective: Our objective was to investigate whether the impact of the SNP on variables of glucose-stimulated insulin secretion is influenced by glucose tolerance status.

Overexpression of kinase-negative protein kinase Cdelta in pancreatic beta-cells protects mice from diet-induced glucose intolerance and beta-cell dysfunction.

Objective: In vitro models suggest that free fatty acid-induced apoptotic beta-cell death is mediated through protein kinase C (PKC)delta. To examine the role of PKCdelta signaling in vivo, transgenic mice overexpressing a kinase-negative PKCdelta (PKCdeltaKN) selectively in beta-cells were generated and analyzed for glucose homeostasis and beta-cell survival.

Research Design And Methods: Mice were fed a standard or high-fat diet (HFD).

Common polymorphisms within the NR4A3 locus, encoding the orphan nuclear receptor Nor-1, are associated with enhanced beta-cell function in non-diabetic subjects.

Background: Neuron-derived orphan receptor (Nor) 1, nuclear receptor (Nur) 77, and nuclear receptor-related protein (Nurr) 1 constitute the NR4A family of orphan nuclear receptors which were recently found to modulate hepatic glucose production, insulin signalling in adipocytes, and oxidative metabolism in skeletal muscle. In this study, we assessed whether common genetic variation within the NR4A3 locus, encoding Nor-1, contributes to the development of prediabetic phenotypes, such as glucose intolerance, insulin resistance, or beta-cell dysfunction.

Methods: We genotyped 1495 non-diabetic subjects from Southern Germany for the five tagging single nucleotide polymorphisms (SNPs) rs7047636, rs1526267, rs2416879, rs12686676, and rs10819699 (minor allele frequencies >or= 0.

Sphingomyelinase dependent apoptosis following treatment of pancreatic beta-cells with amyloid peptides Abeta(1-42) or IAPP.

Amyloid peptides interfere with survival of pancreatic beta-cells. In some cells apoptosis is paralleled by ceramide-dependent alterations of ion channel activity. The purpose of the present study was to elucidate the dependence of amyloid peptides Abeta(1-42) and islet amyloid polypeptide (IAPP)-induced cell death on ceramide formation and ion channel activity in murine pancreatic islet cells.

Regulation of calcineurin activity in insulin-secreting cells: stimulation by Hsp90 during glucocorticoid-induced apoptosis.

Previously, we described that apoptotic cell death induced by the synthetic glucocorticoid dexamethasone (dex) is inhibited by calcineurin inhibitors, FK506 and deltamethrin, in insulin-secreting cells. The aim of the present study was to examine the mechanism of dex-dependent activation of calcineurin. In INS-1 cells cultured up to 4d with dex (100 nmol/l), the percentage of apoptosis, quantified by condensed nuclei and TUNEL positive cells, increased from 1% to 10.

IGF-1 protects against dexamethasone-induced cell death in insulin secreting INS-1 cells independent of AKT/PKB phosphorylation.

Appropriate insulin secretion depends on beta-cell mass that is determined by the balance between cell proliferation and death. IGF-1 stimulates proliferation and protects against apoptosis. In contrast, glucocorticoids promote cell death.

The KATP channel is critical for calcium sequestration into non-ER compartments in mouse pancreatic beta cells.

K(ATP) channel activity influences beta cell Ca(2+) homeostasis by regulating Ca(2+) influx through L-type Ca(2+) channels. The present paper demonstrates that loss of K(ATP) channel activity due to pharmacologic or genetic ablation affects Ca(2+) storage in intracellular organelles. ATP depletion, by the mitochondrial inhibitor FCCP, led to Ca(2+) release from the endoplasmic reticulum (ER) of wildtype beta cells.

Dexamethasone increases Na+/K+ ATPase activity in insulin secreting cells through SGK1.

Glucocorticoids blunt insulin release, an effect partially due to activation of Kv channels. Similar to those channels Na+/K+ ATPase activity repolarizes the plasma membrane. The present study explored whether glucocorticoids increase the Na+/K+ ATPase activity in pancreatic beta-cells.

Dexamethasone induces cell death in insulin-secreting cells, an effect reversed by exendin-4.

Glucocorticoid excess induces hyperglycemia, which may result in diabetes. The present experiments explored whether glucocorticoids trigger apoptosis in insulin-secreting cells. Treatment of mouse beta-cells or INS-1 cells with the glucocorticoid dexamethasone (0.

Effects of I(Ks) channel inhibitors in insulin-secreting INS-1 cells.

Potassium channels regulate insulin secretion. The closure of K(ATP) channels leads to membrane depolarisation, which triggers Ca(2+) influx and stimulates insulin secretion. The subsequent activation of K(+) channels terminates secretion.

Serum- and glucocorticoid-inducible kinase 1 (SGK1) mediates glucocorticoid-induced inhibition of insulin secretion.

Glucocorticoid excess predisposes to the development of diabetes, at least in part through impairment of insulin secretion. The underlying mechanism has remained elusive. We show here that dexamethasone upregulates transcription and expression of the serum- and glucocorticoid-inducible kinase 1 (SGK1) in insulin-secreting cells, an effect reversed by mifepristone (RU486), an antagonist of the nuclear glucocorticoid receptor.