Potent N-(1,3-thiazol-2-yl)pyridin-2-amine vascular endothelial growth factor receptor tyrosine kinase inhibitors with excellent pharmacokinetics and low affinity for the hERG ion channel

A series of N-(1,3-thiazol-2-yl)pyridin-2-amine KDR kinase inhibitors have been developed that possess optimal properties. Compounds have been discovered that exhibit excellent in vivo potency. The particular challenges of overcoming hERG binding activity and QTc increases in vivo in addition to achieving good pharmacokinetics have been acomplished by discovering a unique class of amine substituents. These compounds have a favorable kinase selectivity profile that can be accentuated with appropriate substitution.     

Discovery and evaluation of potent P1 aryl heterocycle-based thrombin inhibitors

In an effort to discover potent, clinically useful thrombin inhibitors, a rapid analogue synthetic approach was used to explore the P(1) region. Various benzylamines were coupled to a pyridine/pyrazinone P(2)-P(3) template. One compound with an o-thiadiazole benzylic substitution was found to have a thrombin K(i) of 0.84 nM. A study of ortho-substituted five-membered-ring heterocycles was undertaken and subsequently demonstrated that the o-triazole and tetrazole rings were optimal. Combination of these potent P(1) aryl heterocycles with a variety of P(2)-P(3) groups produced a compound with an extraordinary thrombin inhibitory activity of 1.4 pM. It is hoped that this potency enhancement in P(1) will allow for more diversification in the P(2)-P(3) region to ultimately address additional pharmacological concerns.     

Discovery of novel phenolic antioxidants as inhibitors of vascular cell adhesion molecule-1 expression for use in chronic inflammatory diseases

Vascular cell adhesion molecule-1 (VCAM-1) mediates recruitment of leukocytes to endothelial cells and is implicated in many inflammatory conditions. Since part of the signal transduction pathway that regulates the activation of VCAM-1 expression is redox-sensitive, compounds with antioxidant properties may have inhibitory effects on VCAM-1 expression. Novel phenolic compounds have been designed and synthesized starting from probucol (1). Many of these compounds demonstrated potent inhibitory effects on cytokine-induced VCAM-1 expression and displayed potent antioxidant effects in vitro. Some of these derivatives (4o, 4p, 4w, and 4x) inhibited lipopolysaccharide (LPS)-induced secretion of pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1 beta (IL-1 beta), and IL-6 from human peripheral blood mononuclear cells (hPBMCs) in a concentration-dependent manner in vitro and showed antiinflammatory effects in an animal model. Compounds 4ad and 4ae are currently in clinical trials for the treatment of rheumatoid arthritis (RA) and prevention of chronic organ transplant rejection, respectively.     

Randomized,controlled, double-blind,multicenter comparison of the cognitive effects of ziprasidone versus olanzapine in acutely ill inpatients with schizophrenia or schizoaffective disorder

Background Newer antipsychotic medications have been reported to enhance cognitive functioning in schizophrenia. Head to head studies with double-blind methods are still relatively few in number.Objectives To compare the relative cognitive enhancing effects of ziprasidone and olanzapine in the treatment of acutely ill inpatients with schizophrenia or schizoaffective disorder.Procedures In this 6-week, multicenter, double-blind, parallel-designed trial, patients were randomized to ziprasidone or olanzapine. No patient who had ever received a complete treatment trial with either of these medications previously was entered into the study. Cognitive testing measuring attention, motor speed, memory, executive functioning, and verbal skills were performed on all patients at baseline and endpoint.Results Treatment with either ziprasidone or olanzapine was associated with statistically significant improvements from baseline in attention, memory, working memory, motor speed, and executive functions. Treatment with olanzapine was also associated with a statistically significant improvement in verbal fluency. No statistically significant differences between these medications were found in the magnitude of improvement from baseline on any of the cognitive measures (other than verbal fluency in an exploratory analysis). Observed changes were not associated with changes in clinical symptoms measured using the PANSS or changes in movement disorders.Conclusions During 6 weeks of treatment, ziprasidone and olanzapine demonstrated substantial and comparable cognitive-enhancing effects relative to previous treatment. These effects were noted in all aspects of cognitive functioning previously proven to predict functional outcome in schizophrenia. No overall differences were detected between the medications in terms of the extent of cognitive enhancement.     

Biochemical properties of a bushmaster snake venom serine proteinase (LV-Ka), and its kinin releasing activity evaluated in rat mesenteric arterial rings

A serine proteinase with kallikrein-like activity (LV-Ka) has been purified to homogeneity from bushmaster snake (Lachesis muta muta) venom. Physicochemical studies indicated that LV-Ka is a single chain glycoprotein with a molecular mass (Mr) of 33 kDa under reducing conditions which was reduced to 28 kDa after treatment with N-Glycosidase F (PNGase F). LV-Ka can be bounded and neutralized by serum alpha2-macroglobulin (alpha2-M), a prevalent mammalian protease inhibitor that is capable of forming a macromolecular complex with LV-Ka (Mr >180 kDa). Cleavage of alpha2-M by the enzyme resulted in the formation of 90-kDa fragments. The proteolytic activity of LV-Ka against dimethylcasein could be inhibited by alpha2-M, and the binding ratio of the inhibitor:enzyme complex was found to be 1:1. The Michaelis constant, Km, and catalytic rate constant, kcat, of LV-Ka on four selective chromogenic substrates were obtained from Lineweaver-Burk plots. LV-Ka exhibits substrate specificities not only for the glandular kallikrein H-D-Val-Leu-Arg-pNA (S-2266) but also for the plasmin substrates S-2251 and Tos-Gly-Pro-Lys-pNA. Bovine kininogen incubated with LV-Ka generated a polypeptide that dose dependently contracted mesenteric arterial rings from spontaneously hypertensive rats (SHR) in a similar way as bradykinin (BK) does. As it happens with BK, LV-Ka generated polypeptide was inhibited by HOE-140, a bradykinin B2-receptor antagonist and by indomethacin, a cyclo-oxygenase inhibitor. These results strongly suggest that the polypeptide generated by LV-Ka by cleavage of bovine kininogen is bradykinin. In addition, our studies may help to understand the mechanism of action involved in hypotension produced by envenomation of bushmaster snake.     

The genetics of bulimia nervosa

Although historically bulimia nervosa has been considered to be a disorder influenced primarily by sociocultural forces such as societal emphasis on thinness and attractiveness, over the past decade it has become increasingly clear that biology and genetics contribute substantially to its etiology. Currently, it is believed that combined study of genetic and environmental risk factors may ultimately hold the clue to the question of why when so many young individuals are exposed to societal risk factors, only a small number actually develop frank eating disorders. Genetic research on eating disorders is progressing in the direction of enhanced explication of the phenotype by focusing on behavioral, neurobiological and temperamental variables that may represent core features of the disorder. Such enhanced phenotyping may assist with identifying areas of the genome that may be implicated in susceptibility to these serious and debilitating conditions.     

Tumor cell-specific BRCA1 and RASSF1A hypermethylation in serum, plasma, and peritoneal fluid from ovarian cancer patients

Because existing surgical and management methods can consistently cure only early-stage ovarian cancer, novel strategies for early detection are required. Silencing of tumor suppressor genes such as p16INK4a, VHL, and hMLH1 have established promoter hypermethylation as a common mechanism for tumor suppressor inactivation in human cancer and as a promising target for molecular detection in bodily fluids. Using sensitive methylation-specific PCR, we screened matched tumor, preoperative serum or plasma, and peritoneal fluid (washes or ascites) DNA obtained from 50 patients with ovarian or primary peritoneal tumors for hypermethylation status of the normally unmethylated BRCA1 and RAS association domain family protein 1A tumor suppressor genes. Hypermethylation of one or both genes was found in 34 tumor DNA (68%). Additional examination of one or more of the adenomatous polyposis coli, p14ARF, p16INK4a, or death associated protein-kinase tumor suppressor genes revealed hypermethylation in each of the remaining 16 tumor DNA, which extended diagnostic coverage to 100%. Hypermethylation was observed in all histologic cell types, grades, and stages of ovarian tumor examined. An identical pattern of gene hypermethylation was found in the matched serum DNA from 41 of 50 patients (82% sensitivity), including 13 of 17 cases of stage I disease. Hypermethylation was detected in 28 of 30 peritoneal fluid DNA from stage IC-IV patients, including 3 cases with negative or atypical cytology. In contrast, no hypermethylation was observed in nonneoplastic tissue, peritoneal fluid, or serum from 40 control women (100% specificity). We conclude that promoter hypermethylation is a common and relatively early event in ovarian tumorigenesis that can be detected in the serum DNA from patients with ovary-confined (stage IA or B) tumors and in cytologically negative peritoneal fluid. Analysis of tumor-specific hypermethylation in serum DNA may enhance early detection of ovarian cancer.     

Cathepsin B mediates caspase-independent cell death induced by microtubule stabilizing agents in non-small cell lung cancer cells

We have previously reported that the microtubule stabilizing agents (MSAs) paclitaxel, epothilone B and discodermolide induce caspase-independent cell death in non-small cell lung cancer (NSCLC) cells. Here we present two lines of evidence indicating a central role for the lysosomal protease cathepsin B in mediating cell death. First, inhibition of cathepsin B, and not of caspases or other proteases, such as cathepsin D or calpains, results in a strong protection against drug-induced cell death in several NSCLC cells. Second, MSAs trigger disruption of lysosomes and release and activation of cathepsin B. Interestingly, inhibition of cathepsin B prevents the appearance of multinucleated cells, an early characteristic of MSA-induced cell death, pointing to a central, proximal role for cathepsin B in this novel cell death pathway.     

Isoprostane levels in the urine of patients with prostate cancer receiving radiotherapy are not elevated

PURPOSE: Previous studies have demonstrated that urinary 8-iso-prostaglandin F (PGF)2alpha serves as a powerful biomarker of lipid peroxidation in diseases in which oxidative stress plays an important role in its pathophysiology. The goal of this study was to measure the urinary isoprostane levels in patients with prostate cancer treated with radiotherapy (RT) in an effort to determine whether isoprostane levels are elevated compared with in historical controls, whether the levels increase after RT, and whether such an increase would correlate positively with the degree of GU symptoms during treatment. METHODS AND MATERIALS: Urine samples were obtained before and during RT from patients enrolled on a recently reported Phase III trial examining the therapeutic efficacy of ibuprofen in decreasing the acute urinary symptoms of RT. Radioimmunoassays were performed on urine samples for 8-iso-PGF2alpha or 15-keto-dihydro-PGF2alpha. RESULTS: Fifteen patients provided samples both before and during RT. The levels of 8-iso-PGF(2alpha) and 15-keto-dihydro-PGF2alpha in the urine samples obtained before prostate RT (0.27 and 0.41 nmol/mmol creatinine) did not differ appreciably from the values observed in a normal cohort (0.27 and 0.46 nmol/mmol creatinine) and did not change after RT (0.23 and 0.37 nmol/mmol creatinine). CONCLUSION: We were unable to detect an increase in either 8-iso-PGF2alpha or 15-keto-dihydro-PGF2alpha in the urine of patients with prostate cancer compared with in historical normal controls. We were also unable to measure an increase in either of the eicosanoids during RT to the prostate gland.