Discretization of Gene Expression Data Unmasks Molecular Subgroups Recurring in Different Human Cancer Types.

Despite the individually different molecular alterations in tumors, the malignancy associated biological traits are strikingly similar. Results of a previous study using renal cell carcinoma (RCC) as a model pointed towards cancer-related features, which could be visualized as three groups by microarray based gene expression analysis. In this study, we used a mathematic model to verify the presence of these groups in RCC as well as in other cancer types.

Genetic algorithm for the design of molecules with desired properties.

The design of molecules with desired properties is still a challenge because of the largely unpredictable end results. Computational methods can be used to assist and speed up this process. In particular, genetic algorithms have proved to be powerful tools with a wide range of applications, e.

GLP-1-analogues resistant to degradation by dipeptidyl-peptidase IV in vitro.

Glucagon-like peptide-1 (GLP-1) stimulates insulin secretion and improves glycemic control in type 2 diabetes. In serum the peptide is degraded by dipeptidyl peptidase IV (DPP IV). The resulting short biological half-time limits the therapeutic use of GLP-1.

Comparison of the effect of native glucagon-like peptide 1 and dipeptidyl peptidase IV-resistant analogues on insulin release from rat pancreatic islets.

Background: Glucagon-like peptide 1 (GLP-1) stimulates insulin secretion and may improve glycaemic control in type 2 diabetes. Therapeutic use is limited by its rapid degradation, primarily by dipeptidyl peptidase IV.

Materials And Methods: Five GLP-1 analogues with alterations at cleavage positions were synthesized according to the Fmoc strategy and tested for metabolic stability by incubation with rat kidney membranes containing dipeptidyl peptidase IV activity.

Endothelial protease-activated receptor-2 induces tissue factor expression and von Willebrand factor release.

A second protease-activated receptor (PAR-2) that could be activated by trypsin or more physiologically by mast cell tryptase has been recently cloned. Both the structure and activation mechanism of PAR-2 was similar to the functional thrombin receptor (PAR-1). Although many effects of the coagulation protease thrombin on the vascular endothelium could be attributed to PAR-1 activation, very little is known about the physiological and pathophysiological role of PAR-2.

Biological activity of GLP-1-analogues with N-terminal modifications.

Glucagon-like peptide-1 (GLP-1) stimulates insulin secretion and improves glycemic control in type 2 diabetes. In serum the peptide is degraded by dipeptidyl peptidase IV (DPP IV). The resulting short biological half-time limits the therapeutic use of GLP-1.

Structural motifs of pituitary adenylate cyclase-activating polypeptide (PACAP) defining PAC1-receptor selectivity.

Pituitary adenylate cyclase-activating polypeptide (PACAP) interacts with three types of PACAP/VIP-receptors. The PAC1-receptor accepts PACAP as a high affinity ligand but not vasoactive intestinal peptide (VIP) similarly binding to VPAC1- and VPAC2-receptors. To identify those amino acids not present in VIP defining PAC1-receptor selectivity of PACAP, radio receptor binding assays on AR4-2J cells were performed.

Cellular handling of unoccupied and agonist-stimulated cholecystokinin receptor determined by immunolocalization.

Cellular handling of receptor molecules is an important mechanism for the regulation of appropriately sensitive hormone-stimulated signaling. Until now, our understanding of the cellular handling of the cholecystokinin (CCK) receptor has been largely limited to following a tagged ligand through the cell. In the present work, we report the application of unique CCK receptor antisera directed toward intracellular domains, which permitted the immunolocalization of this molecule independently of its occupation with ligand.

Relaxant effect of xenin on rat ileum is mediated by apamin-sensitive neurotensin-type receptors.

The action of xenin, a novel 25-residue peptide of the neurotensin (NT)/xenopsin family, was investigated in isolated rat ileal muscle strips and in dispersed longitudinal smooth muscle cells of rat small intestine in vitro. Xenin relaxes KCl-precontracted ileal strips dose dependently (1 nM-3 microM). The order of potency of the investigated peptides was as follows: xenopsin = NT = xenin > neuromedin N.

Trypsin induced von Willebrand factor release from human endothelial cells in mediated by PAR-2 activation.

Nystedt and co-workers cloned in 1994 a second protease activatable receptor (PAR-2) that could be activated by trypsin but not by thrombin (1). In this study, we investigated whether trypsin induced stimulation of endothelial cells is linked to PAR-2 activation. We have found by mRNA analysis that endothelial cells of venous and arterial origin express both protease activatable receptors.

The divergent domains of the NEFA and nucleobindin proteins are derived from an EF-hand ancestor.

The human protein NEFA (DNA binding, EF-hand, Acidic region) has previously been isolated from a KM3 cell line and immunolocalized on the plasma membrane, in the cytoplasma, and in the culture medium. Sequence analysis of a cDNA clone encoding NEFA identified a hydrophilic domain, two EF-hands, and a leucine zipper at the C-terminus. These characters are shared with nucleobindin (Nuc).

GLP-1/GIP chimeric peptides define the structural requirements for specific ligand-receptor interaction of GLP-1.

The gastrointestinal hormones glucagon-like peptide-1 (GLP-1) and gastric inhibitory polypeptide (GIP) strongly stimulate insulin release. Despite their high N-terminal sequence similarity, GLP-1 does not bind to the GIP receptor and vice versa. To characterize the domains required for interaction of the peptide ligands with their specific receptors, we performed displacement studies with various synthetic GLP-1/GIP hybrid peptides on RINm5F insulinoma cells.

Human galanin modulates human colonic motility in vitro. Characterization of structural requirements.

Background: Human galanin (hGal) is a 30-residue non-amidated gut-brain peptide that shows considerable sequence divergence compared with galanin (Gal) forms of other species. Conflicting results have been reported with regard to the structural requirements for its modulatory action on gut motility.

Methods: We investigated the effect of human and rat Gal and substituted analogues of Gal on the contractility of longitudinal muscle strips of the human colon in vitro.

Reactivation of human immunodeficiency virus type 2 in macaques after simian immunodeficiency virus SIVmac superinfection.

By superinfection of human immunodeficiency virus type 2 (HIV-2) strain HIV-2ben-infected macaques with simian immunodeficiency virus (SIV) strain SIVmac, we investigated the mutual influences of an apathogenic and a pathogenic virus in vivo. Four rhesus and two cynomolgus monkeys were infected with HIV-2ben in 1988 and 1989, respectively. Virus could be reisolated from five of six animals 6 weeks after infection.

Specific monoclonal antibodies neutralize the action of PACAP 1-27 or PACAP 1-38 on intestinal muscle strips in vitro.

The gut-brain neuropeptide pituitary adenylate cyclase activating polypeptide (PACAP) is a novel highly conserved member of the secretin-glucagon-VIP peptide family comprising 38 or 27 amino acid residues. In this study, we investigate the actions of PACAP 1-27 or PACAP 1-38 on jejunal and caecal muscle strips from pig or guinea pig and demonstrate the neutralizing effect of two PACAP-specific monoclonal antibodies of the IgG1 subtype, RSP27II and RSP38. These antibodies were used to set up assay systems specific for PACAP 1-27 or PACAP 1-38.

Identification and biochemical characterization of the human brain galanin receptor.

Human galanin (hGal) is an important neuro-modulator present in the brain, gastrointestinal system and the hypothalamo-pituitary axis. A specific receptor for hGal has been identified in various areas in human brain. A single class of high affinity binding sites was found on plasma membranes of the amygdala (Kd 0.

Structure/activity characterization of glucagon-like peptide-1.

Glucagon-like peptide-1 is a gastrointestinal hormone that strongly stimulates insulin release via specific receptors on the pancreatic beta-cell. To characterize the side-chain groups required for interaction of glucagon-like peptide-1 with its receptor, we performed binding studies with alanine-substituted glucagon-like peptide-1 analogues on RINm5F insulinoma cells. The binding affinity and biological activity of glucagon-like peptide-1 have been found to be sensitive to alanine exchanges in the N-terminal positions 1, 4, 6 and the C-terminal positions 22 and 23.

Studies on human porin. XII. Eight monoclonal mouse anti-"porin 31HL" antibodies discriminate type 1 and type 2 mammalian porin channels/VDACs in western blotting and enzyme-linked immunosorbent assays.

Eight mouse monoclonal antibodies directed against the acetylated N-terminal part of the type 1 human VDAC Porin 31HL clearly discriminate type 1 and type 2 mammalian porin channels. This is shown by comparing synthetic N-terminal peptides of either channel type in Western dot blots or by ELISA. The data support the specificity of the anti-Porin 31HL antibodies and thus give further support to our recent observations on extramitochondrial expression of VDAC.

Channel active mammalian porin, purified from crude membrane fractions of human B lymphocytes and bovine skeletal muscle, reversibly binds adenosine triphosphate (ATP).

A new aspect of mammalian porin (mammalian VDAC = mammalian voltage-dependent anion channel) is presented: channel active VDAC binds adenosine triphosphate (ATP) in the absence of Ca2+. Channel active "Porin 31HL" or "Porin 31BM", enriched from crude membranes of human B lymphocytes or whole cell lysates of bovine skeletal muscle, respectively, was bound to a nine atoms spacer ATP-agarose at pH 7.4 or 5.

Purification of the PACAP-1 receptor by ligand affinity chromatography.

Employing the Fmoc solid phase strategy, analogues of pituitary adenylate cyclase activating polypeptide (PACAP) were synthesized containing single cysteine residues. Monobiotinylation of these analogues was achieved via thioether formation between the sulfhydryl groups provided by the cysteine residues and the biotinylation reagent N-lodoacetyl-N'biotinyl-hexylenediamine. Almost all of the S-biotinylated analogues revealed full binding activity to the solubilized PACAP-1 receptor from pig brain membranes.

PACAP and VIP stimulate enzyme secretion in rat pancreatic acini via interaction with VIP/PACAP-2 receptors: additive augmentation of CCK/carbachol-induced enzyme release.

The binding and biological effect of pituitary adenylate cyclase activating polypeptide (PACAP), a novel hypothalamic peptide with high sequence homology to vasoactive intestinal polypeptide (VIP), were studied in rat AR 4-2 J pancreatic carcinoma cells and isolated rat pancreatic acini. PACAP(1-27) and analogue PACAP(1-23, VIP-24-28), but not VIP, displaced potently and reversibly 125I-PACAP(1-27) from binding to an abundantly expressed high affinity PACAP-preferring receptor on AR 4-2 J cells, referred to as "PACAP-1 receptor." High affinity binding was dependent on N-terminal and C-terminal residues of PACAP(1-27): PACAP(1-24,Cys-25) (7.

Principal neutralizing domain of HIV-1 is highly immunogenic when expressed on the surface of hepatitis B core particles.

The development of subunit vaccines against HIV requires the identification of immunologically relevant antigens and a suitable method of antigen delivery. Ideally, defined epitopes with neutralizing activity should be included in a vaccine preparation. The carrier for such peptide sequences should enhance the immunogenicity of the selected epitopes.