Cytohesins are cytoplasmic ErbB receptor activators.

Signaling by ErbB receptors requires the activation of their cytoplasmic kinase domains, which is initiated by ligand binding to the receptor ectodomains. Cytoplasmic factors contributing to the activation are unknown. Here we identify members of the cytohesin protein family as such factors. Cytohesin inhibition decreased ErbB receptor autophosphorylation and signaling, whereas cytohesin overexpression stimulated receptor activation. Monitoring epidermal growth factor receptor (EGFR) conformation by anisotropy microscopy together with cell-free reconstitution of cytohesin-dependent receptor autophosphorylation indicate that cytohesins facilitate conformational rearrangements in the intracellular domains of dimerized receptors. Consistent with cytohesins playing a prominent role in ErbB receptor signaling, we found that cytohesin overexpression correlated with EGF signaling pathway activation in human lung adenocarcinomas. Chemical inhibition of cytohesins resulted in reduced proliferation of EGFR-dependent lung cancer cells in vitro and in vivo. Our results establish cytohesins as cytoplasmic conformational activators of ErbB receptors that are of pathophysiological relevance.

Transition-metal-free azide insertion of N-triftosylhydrazones using a non-metallic azide source.

Benzylic azides, an important class of active organic synthons, were synthesized in high yields from the easily accessible N-triftosylhydrazones with stable TMSN3 under mild conditions. The reaction features high efficiency and excellent functional group tolerance, as illustrated by gram-scale synthesis and the synthesis of drug-like molecules. Mechanistic studies reveal that azidation occurs at the electron-deficient diazo-carbon via the elimination of N2 by an azide ion.

2-Phenyl-1H-imidazol-3-ium hydrogen oxalate.

In the title mol-ecular salt, C(9)H(9)N(2) (+)·C(2)HO(4) (-), the dihedral angle between the aromatic rings of the cation is 17.5 (3)° and the dihedral angle between the -CO(2)H and -CO(2) groups of the anion is 38.6 (2)°. In the crystal, the components inter-act by way of O-H⋯O and N-H⋯O hydrogen bonds.

Reductive radical-initiated 1,2-C migration assisted by an azidyl group.

We report here a novel reductive radical-polar crossover reaction that is a reductive radical-initiated 1,2-C migration of 2-azido allyl alcohols enabled by an azidyl group. The reaction tolerates diverse migrating groups, such as alkyl, alkenyl, and aryl groups, allowing access to n+1 ring expansion of small to large rings. The possibility of directly using propargyl alcohols in one-pot is also described. Mechanistic studies indicated that an azidyl group is a good leaving group and provides a driving force for the 1,2-C migration.

Aptamer displacement identifies alternative small-molecule target sites that escape viral resistance.

Aptamers targeting reverse transcriptase (RT) from HIV-1 inhibit viral replication in vitro, presumably by competing with binding of the primer/template complex. This site is not targeted by the currently available small-molecule anti-HIV-1 RT inhibitors. We have identified SY-3E4, a small-molecule inhibitor of HIV-1 RT, by applying a screening assay that utilizes a reporter-ribozyme regulated by the anti-HIV-1 RT aptamer. SY-3E4 displaces the aptamer from the protein, selectively inhibits DNA-dependent, but not RNA-dependent, polymerase activity, and inhibits the replication of both the wild-type virus and a multidrug-resistant strain. Analysis of available structural data of HIV-1 and HIV-2 RTs rationalizes many of the observed characteristics of the inhibitory profiles of SY-3E4 and the aptamer and suggests a previously not considered region in these RTs as a target for antiviral therapy. Our study reveals unexplored ways for rapidly identifying alternative small-molecule target sites in proteins and illustrates strategies for overcoming resistance-conferring mutations with small molecules.

The presence of serum anti-p53 antibodies from patients with invasive ductal carcinoma of breast: correlation to other clinical and biological parameters.

Breast cancer has been the most common malignant tumor among women in many large cities of China. The aim of this study was to clarify the prognostic significance of serum anti-p53 antibodies (p53 Abs) in Chinese patients of breast cancer. One hundred and forty-four patients with invasive ductal carcinoma of breast were involved in this study. The expressions of ER, PR, c-erbB-2 and p53 were immunostained in tumor tissues and serum p53 Abs were assayed using ELISA method. The correlations between p53 Abs and other clinical and biological markers were analyzed. Among 144 patients, 31 (21.5%) had positive p53 Abs, which was associated with several poor prognostic parameters including higher clinical stage (p = 0.0233), lymph nodes metastasis (p = 0.0033), negative ER expression (p = 0.0250) and positive c-erbB-2 status (p = 0.0227). There was also a strong correlation between p53 Abs and tumor p53 positivity (p < 0.0001). These results indicated that the presence of p53 Abs is probably triggered by the accumulation of tumor p53 protein, and it could be a useful marker to complement routine prognostic factors in breast cancer patients.

Prophylactic vaccination with phage-displayed epitope of C. albicans elicits protective immune responses against systemic candidiasis in C57BL/6 mice.

Epitope LKVIRK on 47 kDa of heat shock protein (Hsp) 90 of Candida albicans, corresponding to residues 386-391 of the Hsp90, is recognized by patients recovering from invasive candidiasis. The efficacy of hybrid phage displaying epitope LKVIRK in the N-terminal region of the major coat protein (pVIII) in inducing anti-invasive candidiasis immune response was studied in C57BL/6 mice. Indirect phage-ELISA results demonstrated that the mice immunized with hybrid phage had significantly higher titers of epitope LKVIRK-specific serum IgG as compared to those immunized with heat-killed C. albicans (HK-CA). C57BL/6 mice immunized either with hybrid phage or with wild-type phage also developed significant levels of delayed-type hypersensitivity (DTH) response and splenocyte proliferation, as well as with HK-CA. In addition, high levels of IFN-gamma in the CD4(+) splenocytes from phage-immunized mice were detected as well during 1 week post-inoculation. Furthermore, mice immunized with hybrid phage acquired a resistance to systemic C. albicans infection as confirmed by fewer C. albicans cells in the kidneys, and had a longer lifespan compared to control groups following intravenous challenge with C. albicans. These results indicate that hybrid phage displaying epitope LKVIRK may serve as a potential vaccine conferring a resistance to systemic candidiasis.