Identification of bicyclic hexafluoroisopropyl alcohol sulfonamides as retinoic acid receptor-related orphan receptor gamma (RORγ/RORc) inverse agonists. Employing structure-based drug design to improve pregnane X receptor (PXR) selectivity

We disclose the optimization of a high throughput screening hit to yield benzothiazine and tetrahydroquinoline sulfonamides as potent RORγt inverse agonists. However, a majority of these compounds showed potent activity against pregnane X receptor (PXR) and modest activity against liver X receptor α (LXRα). Structure-based drug design (SBDD) led to the identification of benzothiazine and tetrahydroquinoline sulfonamide analogs which completely dialed out LXRα activity and were less potent at PXR. Pharmacodynamic (PD) data for compound 35 in an IL-23 induced IL-17 mouse model is discussed along with the implications of a high Y_max in the PXR assay for long term preclinical pharmacokinetic (PK) studies.     

Clinicopathologic features in colorectal cancer patients with microsatellite instability

The microsatellite instability (MSI) mutational pathway is critical to carcinogenesis in a small but significant proportion of colorectal cancers. While MSI is identified in most cancers in individuals with hereditary non-polyposis colorectal cancer, the majority of MSI tumors are found in individuals with sporadic disease. Colorectal cancers arising as a result of MSI have distinct clinicopathologic features distinguishing them from those with microsatellite stability. MSI colorectal cancers affect a larger percentage of women, are usually localized proximal to the splenic flexure, and have a higher incidence of synchronous and metachronous tumors. They are associated with a mucinous histology, tumor-infiltrating lymphocytes, a Crohn's-like inflammatory response, and a higher grade but lower stage. Overall survival is better in individuals with MSI. The benefit of chemotherapy in MSI colorectal cancers, with and without lymph node metastases, remains unclear.     

60Co-γ radiation induces differential acetylation and phosphorylation of histones H3 and H4 in wheat

Histone modifications occur during DNA damage and repair in eukaryotes. These modifications were analysed in wheat seedlings exposed to (60) Co-γ radiation. Seedling height was not significantly affected in the first 2 days after irradiation up to 150 Gy. Subsequently, in the next 2 weeks, there was 30-40% reduction in seedling height, indicating that there were late effects of irradiation. The histones isolated from irradiated seedlings were analysed in the initial stages for modifications of H3 and H4 using antibodies. Global acetylation of H3 decreased and H4 increased in a dose-dependent manner till 100 Gy. The time course of individual modifications showed that for H3K4 and H3K9, acetylation decreased, whereas for H3S10 phosphorylation increased. There were fluctuations in acetylation of H4K5, H4K12 and H4K16, whereas H4K8 showed hyper-acetylation. The results indicate that γ radiation induced DNA damage and repair in wheat seedlings and initiated differential acetylation of H3 and H4. This is the first report in plants on site-specific H3 and H4 modifications in response to exposure to ionizing radiation.     

Effects of environmental factors on basidiospore germination of ammonia fungi <Emphasis Type="Italic">Coprinopsis</Emphasis> spp. collected from different geographical areas

Effects of pH, NH₄-N, and temperature on basidiospore germination in Coprinopsis austrophlyctidospora from New Zealand, C. phlyctidospora from Japan, C. aff. rugosobispora from Canada, and C. echinospora from Canada were investigated. The Coprinopsis spp. required the presence of ammonium-nitrogen under weak alkaline to neutral conditions for germination, regardless of their different areas of occurrence. The former two species had a wider concentration of NH₄Cl solution and pH range for germination in comparison to the latter two species. The optimum concentration of NH₄Cl solution for the germination was 0.01 M in C. austrophlyctidospora and 0.1 M in the other three species. The pH optimum for germination in the former two species was 8.0 whereas that for germination in the latter two species was 8.0–8.5. The temperature range (5.0–40.0°C) for the former two species was wider than that (5–30°C) for the latter two species. Temperature optima for the germination in the former two species, C. aff. rugosobispora and C. echinospora, were 30, 20–25 and 15°C, respectively. The germination abilities of these Coprinopsis species in a wide range of temperatures are relevant to their natural temperature regime, showing their potential ability to propagate in tropical to subarctic regions.     

Preventing DNA over-replication: a Cdk perspective

The basal-like breast cancer, a new category of breast cancer associated with poor prognosis and possibly unique chemosensitivity, is a current topic in the breast cancer field. Evidence from multiple sources strongly indicate that impairment of BRCA1 pathways is responsible for this phenotype, implying the importance of BRCA1 not only in familial breast cancers but also in sporadic cancers. BRCA1 acts as a hub protein that coordinates a diverse range of cellular pathways to maintain genomic stability. BRCA1 participates in multiple cellular supercomplexes to execute its tasks and, in most of the complexes, BRCA1 exists as a RING heterodimer with BARD1 to provide ubiquitin E3 ligase activity that is required for its tumor suppressor function. It was revealed recently that the BRCA1 RING finger is capable of catalyzing multiple types of ubiquitination depending upon the interacting E2, the ubiquitin carrier protein. BRCA1 may catalyze distinct ubiquitination on different substrates as the situation demands. On the other hand, in response to DNA double-strand breaks where BRCA1 plays its major role for homologous recombination repair, recent evidence showed that ubiquitination is a critical step to recruit BRCA1 to the damaged site through UIM (ubiquitin interacting motif) containing protein RAP80. Thus, ubiquitin and BRCA1 likely affect each other in many ways to perform cellular functions. Elucidation of this mechanism in relation to cell survival is now much anticipated because it could be a key to predict chemosensitivity of basal-like breast cancer.     

Bacteria–bacteria interactions within the microbiota of the ancestral metazoan Hydra contribute to fungal resistance

Epithelial surfaces of most animals are colonized by diverse microbial communities. Although it is generally agreed that commensal bacteria can serve beneficial functions, the processes involved are poorly understood. Here we report that in the basal metazoan Hydra, ectodermal epithelial cells are covered with a multilayered glycocalyx that provides a habitat for a distinctive microbial community. Removing this epithelial microbiota results in lethal infection by the filamentous fungus Fusarium sp. Restoring the complex microbiota in gnotobiotic polyps prevents pathogen infection. Although mono-associations with distinct members of the microbiota fail to provide full protection, additive and synergistic interactions of commensal bacteria are contributing to full fungal resistance. Our results highlight the importance of resident microbiota diversity as a protective factor against pathogen infections. Besides revealing insights into the in vivo function of commensal microbes in Hydra, our findings indicate that interactions among commensal bacteria are essential to inhibit pathogen infection.     

Amplified centrosomes may underlie aggressive disease course in pancreatic ductal adenocarcinoma

Centrosome amplification (CA), the presence of centrosomes that are abnormally numerous or enlarged, is a well-established driver of tumor initiation and progression associated with poor prognosis across a diversity of malignancies. Pancreatic ductal adenocarcinoma (PDAC) carries one of the most dismal prognoses of all cancer types. A majority of these tumors are characterized by numerical and structural centrosomal aberrations, but it is unknown how CA contributes to the disease and patient outcomes. In this study, we sought to determine whether CA was associated with worse clinical outcomes, poor prognostic indicators, markers of epithelial-mesenchymal transition (EMT), and ethnicity in PDAC. We also evaluated whether CA could precipitate more aggressive phenotypes in a panel of cultured PDAC cell lines. Using publicly available microarray data, we found that increased expression of genes whose dysregulation promotes CA was associated with worse overall survival and increased EMT marker expression in PDAC. Quantitative analysis of centrosomal profiles in PDAC cell lines and tissue sections uncovered varying levels of CA, and the expression of CA markers was associated with the expression of EMT markers. We induced CA in PDAC cells and found that CA empowered them with enhanced invasive and migratory capabilities. In addition, we discovered that PDACs from African American (AA) patients exhibited a greater extent of both numerical and structural CA than PDACs from European American (EA) patients. Taken together, these findings suggest that CA may fuel a more aggressive disease course in PDAC patients.