BRCA1 and BRCA2 germline mutations in Malaysian women with early-onset breast cancer without a family history

Background

In Asia, breast cancer is characterised by an early age of onset: In Malaysia, approximately 50% of cases occur in women under the age of 50 years. A proportion of these cases may be attributable, at least in part, to genetic components, but to date, the contribution of genetic components to breast cancer in many of Malaysia''s ethnic groups has not been well-characterised.

Methodology

Given that hereditary breast carcinoma is primarily due to germline mutations in one of two breast cancer susceptibility genes, BRCA1 and BRCA2, we have characterised the spectrum of BRCA mutations in a cohort of 37 individuals with early-onset disease (≤40 years) and no reported family history. Mutational analysis of BRCA1 and BRCA2 was conducted by full sequencing of all exons and intron-exon junctions.

Conclusions

Here, we report a total of 14 BRCA1 and 17 BRCA2 sequence alterations, of which eight are novel (3 BRCA1 and 5 BRCA2). One deleterious BRCA1 mutation and 2 deleterious BRCA2 mutations, all of which are novel mutations, were identified in 3 of 37 individuals. This represents a prevalence of 2.7% and 5.4% respectively, which is consistent with other studies in other Asian ethnic groups (4–9%).     

Tesk1 interacts with Spry2 to abrogate its inhibition of ERK phosphorylation downstream of receptor tyrosine kinase signaling

The Sprouty (Spry) proteins function as inhibitors of the Ras-ERK pathway downstream of various receptor tyrosine kinases. In this study, we have identified Tesk1 (testicular protein kinase 1) as a novel regulator of Spry2 function. Endogenous Tesk1 and Spry2 exist in a complex in cell lines and mouse tissues. Tesk1 coexpression relocalizes Spry2 to vesicles including endosomes, inhibiting its translocation to membrane ruffles upon growth factor stimulation. Independent of its kinase activity, Tesk1 binding leads to a loss of Spry2 function as an inhibitor of ERK phosphorylation and reverses inhibition of basic fibroblast growth factor (bFGF)- and nerve growth factor-induced neurite outgrowth in PC12 cells by Spry2. Furthermore, depletion of endogenous Tesk1 in PC12 cells leads to a reduction in neurite outgrowth induced by bFGF. Tesk1 nullifies the inhibitory effect of Spry2 by abrogating its interaction with the adaptor protein Grb2 and interfering with its serine dephosphorylation upon bFGF and FGF receptor 1 stimulation by impeding its binding to the catalytic subunit of protein phosphatase 2A. A construct of Tesk1 that binds to Spry2 but does not localize to the vesicles does not interfere with its function, highlighting the importance of subcellular localization of Tesk1 in this context. Conversely, Tesk1 does not affect interaction of Spry2 with the E3 ubiquitin ligase, c-Cbl, and consequently, does not affect its inhibition of Cbl-mediated ubiquitination of the epidermal growth factor receptor. By selectively modulating the downstream effects of Spry2, Tesk1 may thus serve as a molecular determinant of the signaling outcome.     

Morphological and Inter Simple Sequence Repeat (ISSR) Markers Analyses of Corynespora cassiicola Isolates from Rubber Plantations in Malaysia

Morphological features and Inter Simple Sequence Repeat (ISSR) polymorphism were employed to analyse 21 Corynespora cassiicola isolates obtained from a number of Hevea clones grown in rubber plantations in Malaysia. The C. cassiicola isolates used in this study were collected from several states in Malaysia from 1998 to 2005. The morphology of the isolates was characteristic of that previously described for C. cassiicola. Variations in colony and conidial morphology were observed not only among isolates but also within a single isolate with no inclination to either clonal or geographical origin of the isolates. ISSR analysis delineated the isolates into two distinct clusters. The dendrogram created from UPGMA analysis based on Nei and Li's coefficient (calculated from the binary matrix data of 106 amplified DNA bands generated from 8 ISSR primers) showed that cluster 1 encompasses 12 isolates from the states of Johor and Selangor (this cluster was further split into 2 sub clusters (1A, 1B), sub cluster 1B consists of a unique isolate, CKT05D); while cluster 2 comprises of 9 isolates that were obtained from the other states. Detached leaf assay performed on selected Hevea clones showed that the pathogenicity of representative isolates from cluster 1 (with the exception of CKT05D) resembled that of race 1; and isolates in cluster 2 showed pathogenicity similar to race 2 of the fungus that was previously identified in Malaysia. The isolate CKT05D from sub cluster 1B showed pathogenicity dissimilar to either race 1 or race 2.     

Real-time determination of kinetics of adsorption of lead(II) onto palm shell-based activated carbon using ion selective electrode

In this study, the kinetics of adsorption of Pb(II) from aqueous solution onto palm shell-based activated carbon (PSAC) were investigated by employing ion selective electrode (ISE) for real-time Pb(II) and pH monitoring. Usage of ISE was very appropriate for real-time adsorption kinetics data collection as it facilitated recording of adsorption data at very specific and short time intervals as well as provided consistent kinetics data. Parameters studied were initial Pb(II) concentration and agitation speed. It was found that increases in initial Pb(II) concentration and agitation speed resulted in higher initial rate of adsorption. Pseudo first-order, pseudo second-order, Elovich, intraparticle diffusion and liquid film diffusion models were used to fit the adsorption kinetics data. It was suggested that chemisorption was the rate-controlling step for adsorption of Pb(II) onto PSAC since the adsorption kinetics data fitted both the pseudo second-order and Elovich models well.     

Optimisation of growth medium for the production of cyclodextrin glucanotransferase from Bacillus stearothermophilus HR1 using response surface methodology

Cyclodextrin glucanotransferase (CGTase) activity was observed when the bacterium was grown in the medium at various initial pH values, containing carbon, nitrogen, phosphorus and mineral salt sources at 50 °C for 24 h in the shake flasks. The optimisation of this growth medium was carried out using response surface methodology. The design contains a total of 32 experimental trials involving 10 star points and 6 replicates at the centre points. The design was employed by selecting sago starch, peptone from casein, K₂HPO₄, CaCl₂ and initial pH as five independent variables in this study. The optimal calculated values of tested variables for maximal production of CGTase were found to be comprised of: sago starch, 16.02 g/l; peptone from casein, 20 g/l; K₂HPO₄, 1.4 g/l; CaCl₂, 0.2 g/l and initial pH, 7.54 with a predicted CGTase activity of 14.20 U/ml. These predicted optimal parameters were tested in the laboratory and the final CGTase activity obtained was very close to the predicted value at 14.80 U/ml.     

Anopheles gambiae cadherin AgCad1 binds the Cry4Ba toxin of Bacillus thuringiensis israelensis and a fragment of AgCad1 synergizes toxicity

A midgut cadherin AgCad1 cDNA was cloned from Anopheles gambiae larvae and analyzed for its possible role as a receptor for the Cry4Ba toxin of Bacillus thuringiensis strain israelensis. The AgCad1 cadherin encodes a putative 1735-residue protein organized into an extracellular region of 11 cadherin repeats (CR) and a membrane-proximal extracellular domain (MPED). AgCad1 mRNA was detected in midgut of larvae by polymerase chain reaction (PCR). The AgCad1 protein was localized, by immunochemistry of sectioned larvae, predominately to the microvilli in posterior midgut. The localization of Cry4Ba binding was determined by the same technique, and toxin bound microvilli in posterior midgut. The AgCad1 protein was present in brush border membrane fractions prepared from larvae, and Cry4Ba toxin bound the same-sized protein on blots of those fractions. The AgCad1 protein was expressed transiently in Drosophila melanogaster Schneider 2 (S2) cells. 125I-Cry4Ba toxin bound AgCad1 from S2 cells in a competitive manner. Cry4Ba bound to beads extracted 200 kDa AgCad1 and a 29 kDa fragment of AgCad1 from S2 cells. A peptide containing the AgCad1 region proximal to the cell (CR11-MPED) was expressed in Escherichia coli. Although Cry4Ba showed limited binding to CR11-MPED, the peptide synergized the toxicity of Cry4Ba to larvae. AgCad1 in the larval brush border is a binding protein for Cry4Ba toxin. On the basis of binding results and CR11-MPED synergism of Cry4Ba toxicity, AgCad1 is probably a Cry4Ba receptor.     

Synergism of cellulase enzymes in mixed culture solid substrate fermentation

Sugar cane bagasse was subjected to a mixed culture, solid substrate fermentation with Trichoderma reesei QM9414 and Aspergillus terreus SUK-1 to produce cellulase and reducing sugars. The highest cellulase activity and reducing sugar amount were obtained in mixed culture. The percentage of substrate degradation achieved employing mixed culture was 26% compared to 50% using separate cultures of the two molds. This suggests that the synergism of enzymes in mixed culture solid substrate fermentation have lower synergism than in pure culture.     

Reduction in serum levels of adhesion molecules, interleukin-6 and C-reactive protein following short-term low-dose atorvastatin treatment in patients with non-familial hypercholesterolemia.

Hypercholesterolemia causes endothelial dysfunction, an early feature of atherosclerosis, leading to increased production of adhesion molecules and cytokines. The aim of this study was to investigate the effects of three months of treatment with low dose atorvastatin on serum levels of adhesion molecules, interleukin-6 (IL-6) and highly sensitive C-reactive protein (hs-CRP) in patients with non-familial hypercholesterolemia. Fifty-five patients with non-familial hypercholesterolemia were randomized to treatment with atorvastatin 10 mg/day or placebo for 3 months. Soluble intercellular adhesion molecules-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), E-selectin, IL-6 and hs-CRP levels were measured to assess the inflammatory activity of the endothelium. There was a significant reduction in ICAM-1 at 2 weeks (p<0.0001) with further reduction at 3 months (p<0.0001). At 3 months, there were significant reductions in VCAM-1 (p<0.02), IL-6 (p<0.0001) and hs-CRP (p<0.01), but an increase in E-selectin levels (p<0.002). Treatment with statin was an independent determinant of change in ICAM-1 (p<0.05) and IL-6 levels (p<0.05) after correcting for anthropometric indices, blood pressure and lipid profile. Low-dose atorvastatin treatment leads to reduction in proinflammatory markers of endothelial function, suggesting an attenuation of endothelial activation and improvement in endothelial function, independent of lipid lowering. This may lead to a reduction in the progression of atherosclerosis.     

Dockers at the crossroads.

The family of docker proteins containing phosphotyrosine-binding (PTB) domains appears to represent a family of critically positioned and exquisitely controlled signalling proteins that relay signals from the activated receptors to downstream pathways. These proteins all have a membrane attachment domain, a PTB domain that targets the protein to a subset of receptors and a number of phosphorylatable tyrosines that dock other signalling proteins. Evidence is accruing that suggests that the PTB domain has evolved from a pleckstrin homology (PH) domain to bind to a range of sequences that, while bestowing specificity, allows switching of the docker protein between receptors or signalling systems. The history of the PTB domain and how it influences the participation of docker protein in various signalling pathways are discussed.