Control of Neural Daughter Cell Proliferation by Multi-level Notch/Su(H)/E(spl)-HLH Signaling

The Notch pathway controls proliferation during development and in adulthood, and is frequently affected in many disorders. However, the genetic sensitivity and multi-layered transcriptional properties of the Notch pathway has made its molecular decoding challenging. Here, we address the complexity of Notch signaling with respect to proliferation, using the developing Drosophila CNS as model. We find that a Notch/Su(H)/E(spl)-HLH cascade specifically controls daughter, but not progenitor proliferation. Additionally, we find that different E(spl)-HLH genes are required in different neuroblast lineages. The Notch/Su(H)/E(spl)-HLH cascade alters daughter proliferation by regulating four key cell cycle factors: Cyclin E, String/Cdc25, E2f and Dacapo (mammalian p21CIP1/p27KIP1/p57Kip2). ChIP and DamID analysis of Su(H) and E(spl)-HLH indicates direct transcriptional regulation of the cell cycle genes, and of the Notch pathway itself. These results point to a multi-level signaling model and may help shed light on the dichotomous proliferative role of Notch signaling in many other systems

Seasonal variations in the amount of isoorientin and isovitexin in cecropia glaziovii sneth. leaves over a two-year period

Cecropia glaziovii Sneth (Urticaceae) is a common tree from Southeast and South of Brazil, being widely used in traditional medicine to treat heart and respiratory conditions. C-glycosylflavonoids have being described as the major compounds for this genus, however, no seasonality studies of individual flavonoids was conducted for any Cecropia specie. In this work, the content of isoorientin and isovitexin in aqueous extract from the leaves of C glaziovii during a two-year period was determined by high-performance liquid chromatography with diode array detector (hplc-dad). Seasonal alterations in the content of these two majority C-glycosylflavonoids as well its possible correlation with the pluviosity in the period of January/2008 to January/2010 were determined. Isoorientin presented higher content in November/09 (6.04 mg/g of extract) and lower content in May/08 (1.01 mg/g of extract). The higher content of isovitexin was observed in March/09 and the lower in September/08 (11.42 and 4.47 mg/g of extract, respectively). Although they have distinct behaviors, it was not observed correlation between the values of pluviosity and the production of these C-glycosylflavonoids

Phytochemical study and anti-inflammatory and antioxidant potential of Spondias mombin leaves

Spondias mombin L., Anacardiaceae, is a plant native of Brazil, where it is known as “cajá”. In order to find a potential application for this native species, the anti-inflammatory and antioxidant effects were investigated. The anti-inflammatory activity was evaluated using the in vivo model carrageenan-induced peritonitis in mice. The in vitro antioxidant potential as well the cytotoxicity against 3T3 fibroblast cells also were evaluated. Through High Performance Liquid Chromatography-diode array detector analysis, an analytic method was developed and validated. It allowed the identification and quantification of ellagic acid and chlorogenic acid in hydroethanolic extract of S. mombin leaves. This extract showed anti-inflammatory effect at 100, 200, 300 and 500 mg/kg, however, the ethyl acetate fraction, at 200 mg/kg, showed the highlighted results. Ellagic acid and chlorogenic acid (2.5, 5 and 10 mg/kg) also inhibited the leukocyte migration to the site of inflammation. The extract, fractions and compounds showed significant antioxidant potential when evaluated in different assays. The results shown in this work suggest the anti-inflammatory potential of the leaf extract of S. mombim on peritonitis model induced by carrageenan, it was also observed antioxidant properties associated with an absence of cytotoxicity in cell culture. Further in vivo studies are required to confirm the anti-inflammatories action of S. mombin and its possible anti-inflammatory mechanisms of action. Keywords: Spondias mombin, Chemical marker, Anti-inflammatory and antioxidan

Evolution and clinical impact of co-occurring genetic alterations in advanced-stage EGFR-mutant lung cancers

A widespread approach to modern cancer therapy is to identify a single oncogenic driver gene and target its mutant-protein product (for example, EGFR-inhibitor treatment in EGFR-mutant lung cancers). However, genetically driven resistance to targeted therapy limits patient survival. Through genomic analysis of 1,122 EGFR-mutant lung cancer cell-free DNA samples and whole-exome analysis of seven longitudinally collected tumor samples from a patient with EGFR-mutant lung cancer, we identified critical co-occurring oncogenic events present in most advanced-stage EGFR-mutant lung cancers. We defined new pathways limiting EGFR-inhibitor response, including WNT/β-catenin alterations and cell-cycle-gene (CDK4 and CDK6) mutations. Tumor genomic complexity increases with EGFR-inhibitor treatment, and co-occurring alterations in CTNNB1 and PIK3CA exhibit nonredundant functions that cooperatively promote tumor metastasis or limit EGFR-inhibitor response. This study calls for revisiting the prevailing single-gene driver-oncogene view and links clinical outcomes to co-occurring genetic alterations in patients with advanced-stage EGFR-mutant lung cancer