Novel pharmacological MC4R agonists can efficiently activate mutated MC4R from obese patient with impaired endogenous agonist response.

Human melanocortin 4 receptor (hMC4R) mutations with in vitro functional effects are responsible for 0.5-2.5% of severe obesity.

Fludarabine-mediated suppression of the excision repair enzyme ERCC1 contributes to the cytotoxic synergy with the DNA minor groove crosslinking agent SJG-136 (NSC 694501) in chronic lymphocytic leukaemia cells.

In this study, we set out to establish whether fludarabine could enhance the DNA interstrand crosslinking capacity of SJG-136 in primary human chronic lymphocytic leukaemia (CLL) cells and thereby offer a rationale for its clinical use in combination with SJG-136. SJG-136 rapidly induced DNA crosslinking in primary CLL cells which was concentration-dependent. Further, the level of crosslinking correlated with sensitivity to SJG-136-induced apoptosis (P=0.

Steroid sulfatase: a new target for the endocrine therapy of breast cancer.

Inhibitors of steroid sulfatase are being developed as a novel therapy for hormone-dependent breast cancer in postmenopausal women. Data suggest that steroid sulfatase (STS) activity is much higher than aromatase activity in breast tumors and high levels of STS mRNA expression in tumors are associated with a poor prognosis. STS hydrolyzes steroid sulfates, such as estrone sulfate and dehydroepiandrosterone sulfate (DHEAS), to estrone and DHEA, which can be converted to steroids with potent estrogenic properties, that is, estradiol and androstenediol, respectively.

The toxicology of chemokine inhibition.

The dividing line between essential physiological inflammatory processes and excessive pathological inflammation is often very thin - in some circumstances, indeed, it may be non-existent. Devising anti-inflammatory medications that effectively target only the pathological component therefore remains a central challenge for the pharmaceutical industry. At present, the general rule is that the more powerful the anti-inflammatory effect of a drug, the greater the side-effects that accompany it.

A novel synthetic inhibitor of CDC25 phosphatases: BN82002.

CDC25 dual-specificity phosphatases are essential regulators that dephosphorylate and activate cyclin-dependent kinase/cyclin complexes at key transitions of the cell cycle. CDC25 activity is currently considered to be an interesting target for the development of new antiproliferative agents. Here we report the identification of a new CDC25 inhibitor and the characterization of its effects at the molecular and cellular levels, and in animal models.

Identification of potent non-peptide somatostatin antagonists with sst(3) selectivity.

Using a solution-phase parallel synthesis strategy, a series of non-peptide somatostatin analogues were prepared, and their binding affinities to the five human somatostatin receptor subtypes (sst(1-5)) were determined. Imidazolyl derivatives 2 were found to bind with moderate affinity but with high selectivity to the sst(3) receptor subtype. Further modifications of these structures led to a more potent class of ligands, the tetrahydro-beta-carboline derivatives 4.

Novel non-peptide ligands for the somatostatin sst3 receptor.

A series of imidazole derivatives has been prepared using high throughput parallel synthesis. Several compounds showed high affinity (Ki in 10(-6)-10(-8) M range) and selectivity at recombinant human somatostatin receptor subtype 3 (hsst3).

Synthesis of substituted imidazopyrazines as ligands for the human somatostatin receptor subtype 5.

A new preparation of trisubstituted imidazopyrazines and dihydroimidazopyrazines via parallel synthesis using aminoacids and bromoketones resulted in the discovery of non-peptidic sst5 selective agonists.

Characteristics of the interaction between thrombin exosite 1 and the sequence 269-287 [correction of 269-297] of platelet glycoprotein Ibalpha.

The interaction between GPIb and thrombin promotes platelet activation elicited via the hydrolysis of the thrombin receptor and involves structures located on the segment 238-290 within the N-terminal domain of GPIbalpha and the positively charged exosite 1 on thrombin. We have investigated the ability of peptides derived from the 269-287 sequence of GPIbalpha to interact with thrombin. Three peptides were synthesized, including Ibalpha 269-287 and two scrambled peptides R1 and R2 which are comparable to Ibalpha 269-287 with regards to their content and distribution of anionic residues.

Design and synthesis of new linear and cyclic bradykinin antagonists.

We report here on the synthesis and pharmacological properties of a new series of small linear and cyclic peptides derived from the five C-terminal amino acid residues of second-generation bradykinin receptor antagonists. Variations of the two first residues of the pentapeptide (Thi-Ser-D-Tic-Oic-Arg) were shown to modulate the biological activities of the analogs on bradykinin-induced smooth muscle contractions in rabbit jugular vein (RJV), a tissue preparation specific of the B2 bradykinin receptor. Several analogs showed pA2 values around 7 on this tissue preparation, and one cyclic compound, c[-Gly-Thi-D-Tic-Oic-Arg-], 24, in which Thi-Ser was replaced by Gly-Thi, displayed a pA2 of 7.

Bradykinin B2 receptor involvement in rabbit and murine models of septic shock.

The purpose of our work was to evaluate the role of bradykinin B2 receptors in the early phase (first 3 h) of bacterial lipopolysaccharide (LPS)-induced shock in anesthetized and mechanically ventilated rabbits and to determine if HOE 140, a specific, potent, and long-acting bradykinin B2-receptor antagonist, could improve survival in two murine models of septic shock. In rabbits, LPS injection induced rapid hypotension associated with metabolic acidosis. Three hours after the injection of LPS, we observed leukopenia, thrombocytopenia, and a moderate increase in arterial blood cyclic GMP.

Solution conformation by NMR and molecular modeling of three sulfide-free somatostatin octapeptide analogs compared to angiopeptin.

The conformation in dimethylsulfoxide of the somatostatin derivative angiopeptin and of three disulfide-free analogs was estimated by two-dimensional nuclear magnetic resonance spectroscopy at room temperature. The resulting 3D molecular graphics were compared and shown to reflect the observed differences in the inhibition of restenosis after rat aorta balloon injury by these octapeptide inhibitors. Angiopeptin and its active analog 2 displayed a relatively rigid conformation of the cyclic hexapeptide backbone due to the presence of two well-defined hydrogen bonds, further stabilized by a third hydrogen bond outside the ring.

Effects of the bradykinin B2 receptor antagonist S 16118 (p-guanidobenzoyl-[Hyp3,Thi5,D-Tic7,Oic8]bradykinin) in different in vivo animal models of inflammation.

The effects of S 16118 (p-guanidobenzoyl-[Hyp3,Thi5,D-Tic7, Oic8]bradykinin (BK)], a new, potent and long-acting BK B2 antagonist, were tested in some in vivo models of inflammation. In rats, S 16118 (0.1 and 1 mg/kg) given i.

S 16118 (p-guanidobenzoyl-[Hyp3,Thi5,D-Tic7,Oic8]bradykinin) is a potent and long-acting bradykinin B2 receptor antagonist, in vitro and in vivo.

The in vitro and in vivo effects of S 16118 [p-guanidobenzoyl-[Hyp3, Thi5,D-Tic7,Oic8]bradykinin (BK)], a new BK receptor antagonist, were studied. S 16118 inhibited the contraction produced by BK in the rabbit jugular vein, but was ineffective in the rabbit aorta, indicating the BK B2 receptor specificity of the compound. In isolated organs from various species including humans, S 16118 was a potent antagonist (Ki, pA2 or pKB value from 9.

In vitro effects of HOE 140 in human bronchial and vascular tissue.

Bradykinin is a potent inflammatory mediator which may be involved in various airway diseases. A selective and potent antagonist of the bradykinin B2 receptor has recently been discovered (HOE 140: D-Arg-[Hyp3,Thi5,D-Tic7,Oic8]bradykinin). The purpose of this study was to evaluate the potency of this compound in isolated human tissue (bronchus, pulmonary artery endothelium, umbilical artery and vein smooth muscle).

Agonistic and antagonistic properties of the bradykinin B2 receptor antagonist, Hoe 140, in isolated blood vessels from different species.

1. Hoe 140, a recently described bradykinin B2 antagonist, and NPC 567 from an earlier generation of bradykinin B2 antagonists, were tested in rabbit and sheep isolated blood vessels. 2.

New N alpha-guanidinobenzoyl derivatives of hirudin-54-65 containing stabilized carboxyl or phosphoryl groups on the side chain of phenylalanine-63.

We report on the synthesis and pharmacological properties of a new series of thrombin inhibitors derived from hirudin carboxyl-terminal fragments. Two (arylphosphono)phenylalanines, p-PO3H2-L-Phe1 and m-PO3H2-L-Tyr, and one (carboxymethyl)phenylalanine, p-CH2COOH-L-Phe, were prepared and incorporated into position 63 of the modified hirudin's C-terminal dodecapeptide using the Fmoc solid-phase synthesis strategy. Substitution by any one of the residues led to very active analogs which doubled the thrombin time at low micromolar concentration (Ctt2) in vitro (1 microM < Ctt2 < 3 microM) and potently increased the activated partial thromboplastin time (APTT) ex vivo.

The 50 kDa protein subunit of assembly polypeptide (AP) AP-2 adaptor from clathrin-coated vesicles is phosphorylated on threonine-156 by AP-1 and a soluble AP50 kinase which co-purifies with the assembly polypeptides.

AP50 is a subunit of the assembly polypeptide (AP) subclass AP-2 from bovine brain coated vesicles. It can be phosphorylated in vivo and in vitro on a threonine residue by means of the AP50 kinase activity associated with AP. We have undertaken an analysis of the amino acid sequence around the AP50 phosphorylation site.

Modulation of the activity and assessment of the receptor selectivity in a series of new RGD-containing peptides.

We have investigated the structure-activity relationship of a series of new synthetic RGD analogs and their potential use as specific platelet aggregation inhibitors. Twelve short linear peptides showed high potency to inhibit aggregation in ADP-stimulated dog platelets. In order to assess the selectivity of these analogs towards platelet integrin GPIIb-IIIa, a new cell adhesion inhibition system was devised which was able to discriminate between the two closely related beta 3-integrins of the vasculature, GPIIb-IIIa (alpha IIb beta 3), present in platelets, and the vitronectin receptor (alpha v beta 3), expressed in endothelial cells and platelets.

Synthesis and in vitro activities of new tryptophan-modified and thiomethylene-containing pseudopeptide antagonists of the neurokinins.

A series of pseudopeptide analogs of the substance P-like hexapeptide Ava-Phe-Phe-Gly-Leu-Met-NH2 was produced by N alpha-protection, introduction of the thiomethylene bond, of D- and non-proteinogenic amino acids, and alteration of the side chain of tryptophan. Synthesis of the pseudopeptides on a solid phase was successfully improved by direct formation of the CH2-S bond on the resin. However, while thiomethylene formation between leucine and norleucine led to the expected SS diastereoisomer, the major product of the similar coupling between two phenylalanines was the SR isomer.

Tetrapeptide tachykinin antagonists: synthesis and modulation of the physicochemical and pharmacological properties of a new series of partially cyclic analogs.

We report on the synthesis and the pharmacological properties of a new series of tachykinin antagonists based on the pseudopeptide pharmacophore cyclo[-Abo-Asp(D-Trp-Phe-N(Me)Bzl)-] which contains the 2-azabicyclo[2.2.2]octane-3(S)-carboxylic acid (Abo) residue.

Venous and arterial endothelial cells respond differently to thrombin and its endogenous receptor agonist.

The effects of thrombin and a peptide mimicking the amino terminus of its receptor, Res (42-55), on vascular reactivity were compared in isolated canine blood vessels. In saphenous veins contracted with endothelin-1, both thrombin and Res (42-55) caused relaxation in rings with endothelium and contraction in rings without endothelium. In coronary arteries, thrombin caused similar responses while Res (42-55) only caused contraction.

Molecular cloning and complete amino acid sequence of AP50, an assembly protein associated with clathrin-coated vesicles.

AP50 is the 50,000-dalton protein component found in clathrin-coated vesicles as part of the coat assembly protein (AP) complex, AP-2. AP50 cDNA clones were isolated from rat brain cDNA libraries, and their nucleotide sequence was determined. The isolated cDNA clones represent the entire coding sequence for the rat brain AP50.

Cyclic phosphorylation/dephosphorylation cascade in bovine brain coated vesicles.

Coated vesicles are involved in transport of membrane proteins between several intracellular membrane-bound compartments. These vesicles possess a specific 50-kDa protein which is phosphorylated and dephosphorylated by a coated-vesicle-specific kinase and phosphatase. We studied this phosphorylation/dephosphorylation cascade system and show that the phosphorylation level of the 50-kDa protein is governed by the ATP/ADP ratio.