Angiogenesis inhibitor TX-1898: syntheses of the enantiomers of sterically diverse haloacetylcarbamoyl-2-nitroimidazole hypoxic cell radiosensitizers

(R)- and (S)-Epichlorohydrins were used to prepare the enantiomers of sterically diverse haloacetylcarbamoyl-2-nitroimidazoles that function as hypoxic cell radiosensitizers. The synthetic design allowed for introduction of a side chain of varying bulk that permitted an examination of the steric effects on enantio-discrimination in biological assay systems. The single stereocenter also connected the two pharmacophores--a 2-nitroimidazole moiety critical to hypoxic cell radiosensitization, and a haloacetylcarbamoyl group to function as an anti-angiogenesis pharmacophore. In the chick embryo chorioallantoic membrane (CAM) assay, the R-enantiomers possessing the bulky p-tert-butylphenyl group showed higher anti-angiogenic activity than the corresponding S-enantiomers, while there were no differences in the activity between the enantiomers containing the less bulky methyl and tert-butyl groups. Among the compounds we report, R-p-tert-butylphenyl-bromoacetylcarbamoyl-2-nitroimidazole, TX-1898, was found to be the most promising candidate for further development of as anti-angiogenic hypoxic cell radiosensitizer.     

Synergistic effect of CMP/KDO synthase inhibitors with antimicrobial agents on inhibition of production and release of Vero toxin by enterohaemorrhagic Escherichia coli O157:H7

Synergistic effect of CMP/KDO synthase inhibitors in LPS biosynthesis of Gram-negative bacteria with kanamycin (KM) and fosfomycin (FOM) on the production and release of Vero toxins (VTs) by Escherichia coli O157 was evaluated in vitro. While CMP/KDO synthase inhibitors, KM and FOM showed no inhibitory effect on the production/release of VTs by themselves alone, both KM and FOM showed the remarkable inhibition of VT2 release through synergistic collaboration with CMP:KDO synthase inhibitor.     

Riccardin C: a natural product that functions as a liver X receptor (LXR)alpha agonist and an LXRbeta antagonist

Liver X receptors (LXRs) alpha and beta share considerable sequence homology and several functions, respond to the same endogenous and synthetic ligands, and play critical roles in maintaining lipid homeostasis. In this study, liverwort-derived riccardin C (RC) and F (RF) were identified as an LXRalpha agonist/LXRbeta antagonist and an LXRalpha antagonist, respectively. RC and RF bound to LXRs, but had different abilities to recruit a coactivator and thereby induce transactivation. Despite its unique subtype-selective activity, RC enhanced ABCA1 and ABCG1 expression and cellular cholesterol efflux in THP-1 cells. RC may provide a novel tool for identifying subtype-function and drug development.     

Mutant protein kinase Cgamma found in spinocerebellar ataxia type 14 is susceptible to aggregation and causes cell death

Spinocerebellar ataxia type 14 (SCA14) is an autosomal dominant neurodegenerative disease characterized by various symptoms including cerebellar ataxia. Recently, several missense mutations in the protein kinase Cgamma (gammaPKC) gene have been found in different SCA14 families. To elucidate how the mutant gammaPKC causes SCA14, we examined the molecular properties of seven mutant (H101Y, G118D, S119P, S119F, Q127R, G128D, and F643L) gammaPKCs fused with green fluorescent protein (gammaPKC-GFP). Wild-type gammaPKC-GFP was expressed ubiquitously in the cytoplasm of CHO cells, whereas mutant gammaPKC-GFP tended to aggregate in the cytoplasm. The insolubility of mutant gammaPKC-GFP to Triton X-100 was increased and correlated with the extent of aggregation. gammaPKC-GFP in the Triton-insoluble fraction was rarely phosphorylated at Thr(514), whereas gammaPKC-GFP in the Triton-soluble fraction was phosphorylated. Furthermore, the stimulation of the P2Y receptor triggered the rapid aggregation of mutant gammaPKC-GFP within 10 min after transient translocation to the plasma membrane. Overexpression of the mutant gammaPKC-GFP caused cell death that was more prominent than wild type. The cytotoxicity was exacerbated in parallel with the expression level of the mutant. These results indicate that SCA14 mutations make gammaPKC form cytoplasmic aggregates, suggesting the involvement of this property in the etiology of SCA14.     

The carbohydrate deposits detected by histochemical methods in the molecular layer of the dentate gyrus in the hippocampal formation of patients with schizophrenia, Down's syndrome and dementia, and aged person

Post-mortem brain tissue was obtained from 28 patients with brain disorders, of which 15 had clinically diagnosed schizophrenia, 6 Alzheimer type dementia, 5 dementia with tangles and 2 cases of Down's syndrome. The controls were 22 cases from autopsies without brain disorders or with no known episodes of brain disorder. The tissues were stained for the detection of carbohydrate deposits in the hippocampal formation, using lectin, immunohistochemical and conventional staining methods. The staining revealed the existence of spherical deposits in the inner and middle molecular layers of the dentate gyrus in the hippocampal formation which contained fucose, galactose, N-acetyl galactosamine, N-acetyl glucosamine, sialic acid, mannose and chondroitin sulfate. The number of the deposits was higher in patients with brain disorder such as schizophrenia, Alzheimer type dementia, dementia with tangles or Down's syndrome, and in some aged individuals, in comparison to those in younger individuals. No deposits were detected in a few younger or aged individuals. Spherical deposits 3–10[emsp4 ]m in diameter may be an immature form of the corpora amylacea, since they were similar in the histochemical characteristics with lectin, immunohistochemical and conventional staining methods. However, differing staining ability by hematoxylin, periodic acid Schiff's reagent and antibodies against the intracellular degraded proteins such as ubiquitin and tau-protein was observed. The antibodies against ubiquitin and tau-protein showed clear reactivity with the corpora amylacea and no reactivity with spherical deposits, indicating that the corpora amylacea has an intracellular origin and spherical deposits an extracellular matrix origin. The results obtained in this study indicate that not only neuronal degeneration but also unusual glycometabolism in neurons may disturb the neuronal function and cause brain disorders, and that spherical deposits may cause dysfunction of the neuronal network in the dentate gyrus of the hippocampus which is closely linked with recognition and memory functions.     

Outline of HIV replication and its cellular factors: the track of an invader in the cell

A number of novel findings with reference to HIV replication have been reported even though it passed more than 20 years after a first HIV isolation. Although many cellular factors are known to be involved in the HIV replication, recently investigators discovered novel HIV-suppressive cellular factors such as APOBEC or TRIM5 alpha. Here, I describe and discuss how HIV uses the cellular machinery for its replication.     

Emergence of nuclear heparanase induces differentiation of human mammary cancer cells

The study of epithelial differentiation touches upon many modern aspects of biology. The epithelium is in constant dialogue with the underlying mesenchyme to control stem cell activity, proliferation in transit-amplifying compartments, lineage commitment, terminal differentiation and, ultimately, cell death. There are spatially distinct compartments dedicated to each of these events. Recently we reported that heparanase is expressed in nucleus as well as in the cytoplasm and that nuclear heparanase seems to be related to cell differentiation. In this study, we investigated the role of nuclear heparanase in differentiation by transducing human mammary epithelial cancer cells with heparanase which was delivered specifically into nucleus. We observed that expression of nuclear heparanase allowed the cells to differentiate with the appearance of lipid droplets. This finding supports the idea that heparanase plays a novel role in epithelial cell differentiation apart from its known enzymatic function.     

Schistosoma japonicum: localization of calpain in the penetration glands and secretions of cercariae

A monoclonal antibody was generated against the large subunit of Schistosoma japonicum calpain to study the localization and possible function of the molecule in vivo. Mice were immunized with recombinant S. japonicum calpain and polyclonal antisera and a monoclonal antibody specific to schistosome calpain was obtained. In immunohistochemistry, a monoclonal antibody against S. japonicum calpain, KG-2E11, bound weakly to calpain expressed at the surface of adult worm tegument, however, it bound strongly to the cercarial secretions ("footprints") of S. japonicum, emitted from the penetration glands. The present study indicates that calpain is multifunctional as it is expressed at various locations in different developmental stages. Calpain-based vaccines could thus possibly induce protective immunity against cercariae and the following early developing stages.     

Cooperative effect of hydrophobic and electrostatic forces on alcohol-induced alpha-helix formation of alpha1-acid glycoprotein

Alpha1-acid glycoprotein (AGP) is a serum glycoprotein that mainly binds basic drugs. Previous reports have shown that AGP converts from a beta-sheet to an alpha-helix upon interaction with biomembranes. In the current studies, we found that alkanols, diols, and halogenols all induce this conformational change. Increased length and bulkiness of the hydrocarbon group and the presence of a halogen atom promoted this conversion, whereas the presence of a hydroxyl group inhibited it. Moreover, the effect was dependent on the hydrophobic and electrostatic properties of the alcohols. These results indicate that, in a membrane environment, hydrophobic and electrostatic factors cooperatively induce the transition of AGP from a beta-sheet to an alpha-helix.