Rhomboid domain containing 2 (RHBDD2): A novel cancer-related gene over-expressed in breast cancer

AbstractIn the course of breast cancer global gene expression studies, we identified an uncharacterized gene known as RHBDD2 (Rhomboid domain containing 2) to be markedly over-expressed in primary tumors from patients with recurrent disease. In this study, we identified RHBDD2 mRNA and protein expression significantly elevated in breast carcinomas compared with normal breast samples as analyzed by SAGE (n=46) and immunohistochemistry (n=213). Interestingly, specimens displaying RHBDD2 over-expression were predominantly advanced stage III breast carcinomas (p=0.001). Western-blot, RT-PCR and cDNA sequencing analyses allowed us to identify two RHBDD2 alternatively spliced mRNA isoforms expressed in breast cancer cell lines. We further investigated the occurrence and frequency of gene amplification and over-expression affecting RHBDD2 in 131 breast samples. RHBDD2 gene amplification was detected in 21% of 98 invasive breast carcinomas analyzed. However, no RHBDD2 amplification was detected in normal breast tissues (n=17) or breast benign lesions (n=16) (p=0.014). Interestingly, siRNA-mediated silencing of RHBDD2 expression results in a decrease of MCF7 breast cancer cells proliferation compared with the corresponding controls (p=0.001). In addition, analysis of publicly available gene expression data showed a strong association between high RHBDD2 expression and decreased overall survival (p=0.0023), relapse-free survival (p=0.0013), and metastasis-free interval (p=0.006) in patients with primary ER-negative breast carcinomas. In conclusion, our findings suggest that RHBDD2 over-expression behaves as an indicator of poor prognosis and may play a role facilitating breast cancer progression

Inhibition of cyclooxygenase activity by standardized hydroalcoholic extracts of four Asteraceae species from the Argentine Puna

We determined the anti-inflammatory activity of standardized extracts of four medicinal plant species (Baccharis incarum, B. boliviensis, Chuquiraga atacamensis, Parastrephia lucida) that grow in the Argentine Puna (3800 m above sea level) and that are used to reduce oxidative stress and alleviate gout and arthritic pain. The extracts of plant aerial parts were standardized in terms of total phenolic compounds and flavone/flavanone content and free radical scavenging activity. All extracts showed high phenolic compound concentration (0.5-1.6 mg/mL), mainly flavones and flavonols (0.1-0.8 mg/mL). The extracts showed hydrogen donating ability (DPPH and ABTS) and reactive oxygen species scavenging activity (O2●-, OH-, H2O2). The ability of the extracts to inhibit cyclooxygenase enzymes (COX-1 and COX-2) was determined by calculating percent inhibition of PGE2 production measured by enzyme immunoassay. All extracts inhibited both enzymes with IC50 values of 2.0 to 16.7 µg/mL. The anti-inflammatory activity of B. incarum and C. atacamensis extracts was higher than that of B. boliviensis and P. lucida. The IC50 values obtained for indomethacin were 0.11 and 0.78 µM for COX-1 and COX-2, respectively. The present results are consistent with the anecdotal use of these species in phytotherapic preparations

Stabilization of Lisosome Membrane by Species from Asteraceae, Ephedraceae, Frankeniaceae, Solanaceae, Rosaceae and Verbenaceae Families

In inflammation, many leucocytes are damaged or destroyed; in result, their lisosomal enzymes are spread to the extracellular medium, damaging the tissue of the swollen area. This induces the synthesis of more inflammation mediators and worsens the inflammation. Plants are a promising source of metabolites with important bio-activities and a potential usage in the treatment of illness related to inflammatory process. We evaluated seventeen plant species' ability to stabilize lisosome membrane, inferred by their capacity to protect red blood cells' membrane. Plant species were recollected from arid regions of Northwest Argentina and its tinctures' ability to protect red blood cells? (RBC) membrane was evaluated by using a hypotonic saline solution and spectrophotometrical quantification of the hemoglobin released. As positive controls, anti-inflammatory drugs were used. The majority of the studied species were able to stabilize the RBC membrane, except for Ephedra multiflora and Frankenia triandra. The plant species that prevented the lyses of 50% or more RBC at 1.5 mg/ml were: Baccharis boliviensis, B. incarum, Chiliotrichiopsis keidelii, Parastrephia lepidophylla, P. phyliciformis, Fabiana bryoides, F. patagonica and Junellia seriphioides. In comparison to the anti-inflammatory drugs tested, some species showed a higher effect.Fil: Torres Carro, R.. No especifíca;Fil: Alberto, Maria Rosa. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Química del Noroeste. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia. Instituto de Química del Noroeste; ArgentinaFil: Isla, M.I.. No especifíca

Effects of Zuccagnia punctata extracts and their flavonoids on the function and expression of ABCB1/P-glycoprotein multidrug transporter

ETHNOPHARMACOLOGICAL RELEVANCE: Zuccagnia punctata extracts (ZpE) are used in ethnomedicine as antimicrobial and anti-inflammatory drugs. The pharmacological properties of ZpE and their polyphenolic components suggest that they may be used as potential modulators on the P-glycoprotein (P-gp) multidrug transporter. P-gp is well known for its role in the acquired drug resistance by tumors following chemotherapy, causing a low drug bioavailability by extruding them out of the cells. AIM OF STUDY: To evaluate the effects of ZpE and three of their phenolic components: 7-hydroxyflavanone (HF), 3,7-dihydroxyflavone (DHF) and 2',4'-dihydroxychalcone (DHC) on P-gp activity and expression. MATERIAL AND METHODS: The effects of natural products on ABCB1/P-gp function and expression were evaluated by R-123 accumulation assay and western blot analysis using HK-2 cells as experimental model. The ABCB1 mRNA content was determined by SQRT-PCR. RESULTS: The accumulation of R-123 in HK-2 cells was significantly increased by ZpE and DHF, and to a lesser extent by DHC, indicating their roles on the efflux transporter activity. However, HF did not show any effect. HK-2 cells maintained in the presence of ZpE or DHF for 72 h, showed an increase in P-gp expression whereas activity was unchanged or decreased. No changes were observed in ABCB1 mRNA content. Furthermore, in these assay conditions, more sensibility of HK-2 cells to the cytotoxic action of cyclosporine A (P-gp substrate) was observed. CONCLUSION: These results may suggest an impact of Zuccagnia punctata and some of its components on the pharmacokinetics of drugs that are P-gp substrates, as well as a potential role on multidrug resistance modulation

Antimicrobial phenylpropanoids from the Argentinean highland plant Parastrephia lucida (Meyen) Cabrera

Quispe, C (Quispe, Cristina); Schmeda-Hirschmann, G (Schmeda-Hirschmann, Guillermo). Univ Talca, Inst Quim Recursos Nat, Talca, ChileEthnopharmacological relevance: The Argentinean highland plant Parastrephia lucida (Meyen) Cabrera is used in traditional medicine as an antiseptic and anti-inflammatory crude drug. Aim of the study: To relate the antimicrobial effect of the crude drug with the constituents of the active fractions and traditional use. Materials and methods: Assay-guided isolation of the methanol (MeOH) plant extract was carried out using bacteria and yeasts as target organisms. Both ATCC and local strains were included in the study. The antimicrobial fractions and compounds were detected by bioautographic assays. Minimum inhibitory concentrations (MIC) of each extract and fraction were determined and compared with reference antibiotics. Fractions were analyzed by HPLC-DAD, GC-MS, H-1 NMR and C-13 NMR. Results: From the MeOH extract of the plant, assay-guided isolation of the antimicrobial constituents led to 12 phenylpropanoids and two simple phenolics. Most of the compounds occurring in the active fractions were E-caffeoyl or E-cinnamoyl esters including prenyl and phenethyl derivatives. The MIC values of the most active fractions ranged between 12.5 and 200 mu g/mL against reference strains and local isolates of Staphylococcus aureus and Enterococcus faecalis. Conclusions: The antimicrobial effect found in the crude drug was associated with mixtures of phenylpropanoids, including prenyl and phenethyl esters of caffeic and cinnamic acids. The results support at least in part the traditional use of the plant as local antiseptic. (C) 2012 Elsevier Ireland Ltd. All rights reserved