Benzothiepin-derived molecular scaffolds for estrogen receptor modulators: synthesis and antagonistic effects in breast cancer cells

A series of novel benzothiepin-derived compounds are described as potent selective modulators of the human estrogen receptor (SERMs). The objective of the study is to evaluate the antiproliferative effects of the compounds on human MCF-7 breast tumor cells. These heterocyclic compounds contain the traditional triarylethylene arrangement exemplified by tamoxifen, conformationally restrained through the incorporation of the benzothiepin ring system. The compounds demonstrated potency at nanomolar concentrations in antiproliferative assays against an MCF-7 human breast cancer cell line with low cytotoxicity. The compounds exhibited low nanomolar binding affinity for the estrogen receptor (ER) with some specificity for ERbeta, and also demonstrate potent antiestrogenic properties in the human uterine Ishikawa cell line. The effect of a number of functional group substitutions on the ER binding properties of the benzothiepin molecular scaffold is explored through a brief computational structure-activity relationship investigation with molecular simulation.     

Differential expression of interferon responsive genes in rodent models of transmissible spongiform encephalopathy disease

Background

Alzheimer's disease (AD) is characterized by a decline in cognitive function and accumulation of amyloid-β peptide (Aβ) in extracellular plaques. Mutations in amyloid precursor protein (APP) and presenilins alter APP metabolism resulting in accumulation of Aβ42, a peptide essential for the formation of amyloid deposits and proposed to initiate the cascade leading to AD. However, the role of Aβ40, the more prevalent Aβ peptide secreted by cells and a major component of cerebral Aβ deposits, is less clear. In this study, virally-mediated gene transfer was used to selectively increase hippocampal levels of human Aβ42 and Aβ40 in adult Wistar rats, allowing examination of the contribution of each to the cognitive deficits and pathology seen in AD.

Results

Adeno-associated viral (AAV) vectors encoding BRI-Aβ cDNAs were generated resulting in high-level hippocampal expression and secretion of the specific encoded Aβ peptide. As a comparison the effect of AAV-mediated overexpression of APPsw was also examined. Animals were tested for development of learning and memory deficits (open field, Morris water maze, passive avoidance, novel object recognition) three months after infusion of AAV. A range of impairments was found, with the most pronounced deficits observed in animals co-injected with both AAV-BRI-Aβ40 and AAV-BRI-Aβ42. Brain tissue was analyzed by ELISA and immunohistochemistry to quantify levels of detergent soluble and insoluble Aβ peptides. BRI-Aβ42 and the combination of BRI-Aβ40+42 overexpression resulted in elevated levels of detergent-insoluble Aβ. No significant increase in detergent-insoluble Aβ was seen in the rats expressing APPsw or BRI-Aβ40. No pathological features were noted in any rats, except the AAV-BRI-Aβ42 rats which showed focal, amorphous, Thioflavin-negative Aβ42 deposits.

Conclusion

The results show that AAV-mediated gene transfer is a valuable tool to model aspects of AD pathology in vivo, and demonstrate that whilst expression of Aβ42 alone is sufficient to initiate Aβ deposition, both Aβ40 and Aβ42 may contribute to cognitive deficits.     

Identification of a Secreted Fatty Acid and Retinol-Binding Protein (Hp-FAR-1) from Heligmosomoides polygyrus

Hp-FAR-1 is a major, secreted antigen of the parasitic nematode Heligmosomoides polygyrus, a laboratory mouse model frequently used to study the cellular mechanisms of chronic helminth infections. The DNA encoding Hp-FAR-1 was recovered by screening a fourth larval (L(4)) H. polygyrus cDNA expression library using antibodies raised against L(4) stage excretory/secretory (E/S) proteins. Predictions of secondary structure based on the Hp-FAR-1 amino acid sequence indicated that an alpha-helix predominates in Hp-FAR-1, possibly with some coiled-coil conformation, with no beta-structure. Fluorescence-based ligand binding analysis confirmed that the recombinant Hp-FAR-1 (rHp-FAR-1) binds the fluorescent fatty acid analog 11-((5-[dimethylaminoaphthalene-1-sulfonyl)amino)undecanoic acid (DAUDA), and by competition oleic acid. RT-PCR amplification of the hp-far-1 gene indicated that the gene is transcribed in all parasitic stages of the organism's life cycle. The presence of a secreted FAR protein in the well-defined laboratory model of H. polygyrus provides an excellent model for the further study and analysis of the in vivo role of secreted FAR proteins in parasitism, and supports the mounting evidence that secreted FAR proteins play a major role in nematode parasitism.     

Ginseng root water-extracted pectic polysaccharides originate from secretory cavities

A range of molecular probes for cell wall polysaccharides has been used to explore the structure and location of water-extracted pectic polysaccharides occurring in fractions isolated from ginseng roots. The LM19 homogalacturonan (HG) epitope was abundant in an HG fraction and analysis of LM19 binding to a rhamnogalacturonan-I (RG-I) rich-fraction indicated that the LM19 epitope is sensitive to acetylation. A specific RG-I epitope (LM16), four arabinogalactan-protein (AGP) epitopes (LM2, LM14, JIM16, MAC207) and an extensin epitope (JIM20) were found to be abundant and co-located in several isolated polysaccharide fractions including an arabinogalactan fraction and two RG-I fractions. Detection of the RG-I, AGP and extensin epitopes identified in isolated polysaccharide fractions in sections of ginseng roots indicated that they were most abundant in secretory cavities found in the cortical regions of ginseng roots. In addition, the immunocytochemical study indicated that polysaccharide epitope masking is a widespread phenomenon in the primary cell walls of ginseng roots.     

AGT M235T genotype/anxiety interaction and gender in the HyperGEN study

Background

Both anxiety and elevated heart rate (HR) have been implicated in the development of hypertension. The HyperGen cohort, consisting of siblings with severe and mild hypertension, an age-matched random sample of persons from the same base populations, and unmedicated adult offspring of the hypertensive siblings (N = 1,002 men and 987 women), was analyzed for an association of the angiotenisinogen AGTM235T genotype (TT, MT, MM) with an endophenotype, heart rate (HR) in high and low anxious groups.

Methodology

The interaction of AGTM genotype with anxiety, which has been independently associated with hypertension, was investigated adjusting for age, hypertension status, smoking, alcohol consumption, beta blocker medication, body mass index, physical activity and hours of television viewing (sedentary life style).

Principal Findings

Although there was no main effect of genotype on HR in men or women, high anxious men with the TT genotype had high HR, whereas high anxious men with the MM genotype had low HR. In women, HR was inversely associated with anxiety but there was no interaction with genotype.

Conclusion/Significance

The results suggest that high anxiety in men with the TT genotype may increase risk for hypertension whereas the MM genotype may be protective in high anxious men. This type of gene x environment interaction may be one reason why genome wide association studies sometimes fail to replicate. The locus may be important only in combination with certain environmental factors.     

A weak C' box renders U3 snoRNA levels dependent on hU3-55K binding

The rate of ribosome biogenesis, which is downregulated in terminally differentiated cells and upregulated in most cancers, regulates the growth rate and is linked to the cell's proliferative potential. The U3 box C/D small nucleolar RNP (snoRNP) is an integral component of the small subunit (SSU) processome and is essential for 18S rRNA processing. We show that U3 snoRNP assembly, and therefore U3 snoRNA accumulation, is regulated through the U3-specific protein hU3-55K. Furthermore, we report that the levels of several SSU processome components, including the U3 snoRNA but not other box C/D snoRNAs, are specifically downregulated during human lung (CaCo-2) and colon (CaLu-3) epithelial cell differentiation. c-Myc is reported to play an integral role in regulating ribosome production by controlling the expression of many ribosome biogenesis factors. Our data, however, indicate that this regulation is not dependent on c-Myc since the level of this protein does not change during epithelial cell differentiation. In addition, depletion of c-Myc had only a mild affect on the levels of SSU processome proteins. CaCo-2 cells are colon adenocarcinoma epithelial cells that are believed to revert to their precancerous state during differentiation. This suggests a significant increase in the levels of specific SSU processome components during tumorogenesis.     

The death domain kinase RIP1 links the immunoregulatory CD40 receptor to apoptotic signaling in carcinomas

CD40, a tumor necrosis factor (TNF) receptor family member, is widely recognized for its prominent role in the antitumor immune response. The immunostimulatory effects of CD40 ligation on malignant cells can be switched to apoptosis upon disruption of survival signals transduced by the binding of the adaptor protein TRAF6 to CD40. Apoptosis induction requires a TRAF2-interacting CD40 motif but is initiated within a cytosolic death-inducing signaling complex after mobilization of receptor-bound TRAF2 to the cytoplasm. We demonstrate that receptor-interacting protein 1 (RIP1) is an integral component of this complex and is required for CD40 ligand-induced caspase-8 activation and tumor cell killing. Degradation of the RIP1 K63 ubiquitin ligases cIAP1/2 amplifies the CD40-mediated cytotoxic effect, whereas inhibition of CYLD, a RIP1 K63 deubiquitinating enzyme, reduces it. This two-step mechanism of apoptosis induction expands our appreciation of commonalities in apoptosis regulatory pathways across the TNF receptor superfamily and provides a telling example of how TNF family receptors usurp alternative programs to fulfill distinct cellular functions.     

Preliminary SAR studies on non-apamin-displacing 4-(aminomethylaryl)pyrrazolopyrimidine K(Ca) channel blockers

An exploratory SAR study on a series of potent, non-apamin-displacing 4-(aminomethylaryl)pyrazolopyrimidine K(Ca) channel blockers is described and their selectivity against K(Ca) channel subtypes is reported. The most potent analog, 5-chloro-N-(thiophen-2-ylmethyl)pyrazolo[1,5-a]pyrimidin-7-amine (24) displayed sub-micromolar activity in both a thallium flux and whole-cell electrophysiology assay and did not displace apamin in a competitive binding study.     

Initial SAR studies on apamin-displacing 2-aminothiazole blockers of calcium-activated small conductance potassium channels

An initial SAR study on a series of apamin-displacing 2-aminothiazole K(Ca)2 channel blockers is described. Potent inhibitors such as N-(4-methylpyridin-2-yl)-4-(pyridin-2-yl)thiazol-2-amine (13) are disclosed, and for select members of the series, the relationship between the observed activity in a thallium flux, a binding and a whole-cell electrophysiology assay is presented.     

Intravenous Shiga toxin 2 promotes enteritis and renal injury characterized by polymorphonuclear leukocyte infiltration and thrombosis in Dutch Belted rabbits

Enterohemorrhagic Escherichia coli (EHEC) infection causes hemolytic uremic syndrome, a leading cause of acute renal failure in children. Dutch Belted (DB) rabbits are susceptible to EHEC-induced disease. Using real-time quantitative RT-PCR we measured the renal mRNA expression of cytokines and fibrinolytic factors in DB rabbits challenged with intravenous Shiga toxin 2 (Stx2) (1200 ng/kg). Group 1 rabbits received an incremental dose during an 8-day period whereas Group 2 rabbits received a single dose. Group 1 rabbits developed mild disease. In contrast, Group 2 rabbits developed severe diarrhea, higher levels of circulating polymorphonuclear leukocytes, increased mean platelet volume, and increased fibrinogen levels. Group 2 rabbits developed polymorphonuclear leukocyte infiltration in the intestine and kidney as well as glomerular congestion, luminal constriction, and mesangial glomerulonephropathy. These renal lesions were associated with up-regulation of interleukin-8 (P<0.006), plasminogen activator inhibitor-1 (P<0.04), and tissue plasminogen activator (P<0.05). Circulating Stx2 promoted dose-dependent enteritis and renal injury characterized by inflammation and impaired fibrinolysis leading to thrombosis.