Expression of the G6PD locus on the human X chromosome is associated with demethylation of three CpG islands within 100 kb of DNA.

We have previously reported that expression of the G6PD locus is correlated with the methylation status of two islands of CpG dinucleotides which are 3' to the locus and in the 5' region of two adjacent genes of unknown function, P3 and GdX. We have now examined the methylation of a third CpG island in the promoter region of the G6PD gene itself in DNA from males, females and reactivants that express G6PD on the inactive X chromosome. Our results show that expression of the G6PD gene is associated with concordant demethylation of all three CpG islands in this 100-kb region of DNA.     

'Click' synthesis of a triazole-based inhibitor of Met functions in cancer cells

The use of Cu(I)-catalyzed azide-alkyne 1,3-dipolar cycloaddition permitted the synthesis of a new compound that is able to inhibit the HGF-induced scattering of MDCK (epithelial cells) and in vitro tumorigenesis of H1437 (non-small-cell lung cancer) and GTL-16 (human gastric carcinoma). In agreement with biochemical and biological results, docking studies within the ATP binding site of Met suggested for the new synthesized compound a binding mode similar to that of the active compound Triflorcas previously reported.     

Combined Drug Action of 2-Phenylimidazo[2,1-b]Benzothiazole Derivatives on Cancer Cells According to Their Oncogenic Molecular Signatures

The development of targeted molecular therapies has provided remarkable advances into the treatment of human cancers. However, in most tumors the selective pressure triggered by anticancer agents encourages cancer cells to acquire resistance mechanisms. The generation of new rationally designed targeting agents acting on the oncogenic path(s) at multiple levels is a promising approach for molecular therapies. 2-phenylimidazo[2,1-b]benzothiazole derivatives have been highlighted for their properties of targeting oncogenic Met receptor tyrosine kinase (RTK) signaling. In this study, we evaluated the mechanism of action of one of the most active imidazo[2,1-b]benzothiazol-2-ylphenyl moiety-based agents, Triflorcas, on a panel of cancer cells with distinct features. We show that Triflorcas impairs in vitro and in vivo tumorigenesis of cancer cells carrying Met mutations. Moreover, Triflorcas hampers survival and anchorage-independent growth of cancer cells characterized by “RTK swapping” by interfering with PDGFRβ phosphorylation. A restrained effect of Triflorcas on metabolic genes correlates with the absence of major side effects in vivo. Mechanistically, in addition to targeting Met, Triflorcas alters phosphorylation levels of the PI3K-Akt pathway, mediating oncogenic dependency to Met, in addition to Retinoblastoma and nucleophosmin/B23, resulting in altered cell cycle progression and mitotic failure. Our findings show how the unusual binding plasticity of the Met active site towards structurally different inhibitors can be exploited to generate drugs able to target Met oncogenic dependency at distinct levels. Moreover, the disease-oriented NCI Anticancer Drug Screen revealed that Triflorcas elicits a unique profile of growth inhibitory-responses on cancer cell lines, indicating a novel mechanism of drug action. The anti-tumor activity elicited by 2-phenylimidazo[2,1-b]benzothiazole derivatives through combined inhibition of distinct effectors in cancer cells reveal them to be promising anticancer agents for further investigation.     

Phragmidium satoanum,a new rust pathogen of Rosa hirtula in Japan

The causal fungus of a rust disease of Rosa hirtula, endemic to mountainous areas of Fuji-Hakone-Izu National Park, Japan, was thought to be a common species Phragmidium rosae-multiflorae. Continued field observations, morphological examination, and experimental inoculations proved that the fungus produced laterally three-angled aeciospores and urediniospores together with multi-cellular teliospores on the same R. hirtula trees. These morphological features were different from those of P. rosae-multiflorae. The fungus parasitized only R. hirtula. Experimental inoculations and field observations did not prove that R. banksiae, R. laevigata, and R. multiflora supported infection and sporulation of the fungus. Under the field observations, R. multiflora, the most common host of P. rosae-multiflorae, was not proven to harbor the R. hirtula fungus. Therefore, the fungus was concluded to be a species distinct from P. rosae-multiflorae; and a new name, P. satoanum, was proposed for it.     

Novel cyclized Pifithrin-alpha p53 inactivators: synthesis and biological studies

Starting from various cyclic or bicyclic ketones, we have synthesized novel Pifithrin-alpha analogues bearing different methyl substituted phenyl ketone groups at the N3-position of the 2-iminothiazole heterocycle. From stability studies in a biological medium as well as under specific chemical conditions, we have shown by NMR techniques that through a dehydration process, some derivatives can generate their corresponding cyclized analogues. All of the new analogues, Pifithrin-like and polycyclic dehydrated derivatives were assessed for their p53 inactivation potency by measuring survival of cortical neurons, whose death was induced by the DNA-damaging agent etoposide. Pifithrin-alpha like 2f as well as the cyclic dehydrated 6b analogue were found to be one log more potent p53 inactivators than reference compound Pft-alpha, with EC50 values ranging around 30 nM. These results support the finding that p53 inactivation by Pft-alpha analogues could be also due to the presence of the cyclic dehydrated Pft-alpha forms, generated in situ in the biological assay incubation medium.     

Length Control of the Flagellar Hook in a Temperature-Sensitive flgE Mutant of Salmonella enterica Serovar Typhimurium

The flagellar hook is a short, curved, extracellular structure located between the basal body and the filament. The hook is composed of the FlgE protein. In this study, we analyzed flagellum assembly in a temperature-sensitive flgE mutant of Salmonella enterica serovar Typhimurium. When the mutant cells were grown at 30°C, they produced flagella of a normal length (71% of the population) and short hooks without filaments (26%). At 37°C, 70% of the basal bodies lacked hooks, and intact flagella made up only 6% of the population. Mutant cells secreted monomeric FlgE in abundance at 37°C, suggesting that the mutant FlgE protein might be defective in polymerization at higher temperatures. The average length of the hooks in intact filaments was 55 nm, whereas after acid treatment, it was 45 nm. SDS-PAGE analysis of the hook-basal body showed that HAP1 was missing in the mutant but not in the wild type. We concluded that hook length in the mutant is controlled in the same way as in the wild type, but the hook appeared short after acid treatment due to the lack of HAP1. We also learned that the true length of the hook is possibly 45 nm, not 55 nm, as has been believed.     

The CD5+ B-cell

In the last two decades, many efforts have been made to better understand the biology of B-lymphoproliferative disorders through the knowledge of physiology and function of the postulated normal counterpart. The follicular mantle B-cells express a typical CD23+ IgM+ IgD+ phenotype and surround the germinal center area in secondary lymphoid organs. CD5+ B-cells with FM phenotype can be isolated from different sources and all share similar morphologic, phenotypic and functional features (small cells, scanty nucleus/cytoplasm ratio, unmutated VH genes, response to polyclonal activators but not to T independent antigens, production of "natural" antibodies). While the CD5+ B-cells predominate in fetal life, their number decreases with age. However, the CD5+ B-cells have been demonstrated to increase again in elderly both in man and mouse. This finding may explain the incidence of B-CLL and of MCL that are believed to represent the malignant transformation of the normal CD5+ B-cells, among elderly and middle aged individuals, respectively.