[Residues affecting hydrolysis of soy isoflavone glycosides, stability and catalytic properties of Thermotoga maritime β-glucosidase]

The thermostable β-glucosidase A (TmBglA) from Thermotoga maritime is a promising biocatalyst for production of isoflavone aglycones. Use of enzymes with high specificity for soy isoflavone conjugates is however essential for efficient hydrolysis. The effect of the amino acids located in the aglycone binding pocket with non-conserved residues between specificity groups in family 1 glycoside hydrolase (GH1) was studied using wild-type TmBglA and 3 exchange mutants (MI-TmBglA, M2-TmBglA, M1M2-TmBglA). Three mutants were expressed in Escherichia coli, purified and characterized. They had shifts in both optimum tem- perature and thermal stability, and their narrowing pH-activity curve caused by removing the ionized side chain in mutation. All mutants demonstrated the decreased catalytic efficiency more effectively revealed with natural glycoside, salicin, than with artificial substrate, p-nitrophenyl-β-D-glucopyranoside, suggesting that' these amino acids are the key residues to determine aglycone specificity. A lower hydrolysis of genistin and daidzin for M2-TmBglA than M1-TmBglA indicated that L400, A407 and E408 being preferable to V170, A171, V173, G 174 and H180 residues of Tm-BglA could be essential for soy isoflavone glycoside binding and catalysis.

Electrolytic partitioning of uranium and plutonium based on a new type of electrolytic mixer-settler

The design of a new type of electroreduction mixer-settler for the partitioning of uranium and plutonium during the Purex process, which is featured with E-shaped cathodes and U-shaped anodes in settling chamber, is described and the operational results achieved using this equipment are presented. The results show that this new type of mixer-settler has excellent separation performances. The flow rate of organic feed solution is 3 mL/min and the flow ratio of feed solution (1BF) to aqueous back extraction stream (1BX) and to organic wash stream (1BS) is 4/1/1. For an organic feed of 84 g/L uranium and 1.40 ⁓ 2.64 g/L plutonium, both the separation factor of plutonium from uranium and that of uranium from plutonium are apparently higher than 104

Targeted delivery of siRNA-generating DNA nanocassettes using multifunctional nanoparticles

Molecular therapy using a small interfering RNA (siRNA) has shown promise in the development of novel therapeutics. Various formulations have been used for in vivo delivery of siRNAs. However, the stability of short double-stranded RNA molecules in the blood and efficiency of siRNA delivery into target organs or tissues following systemic administration have been the major issues that limit applications of siRNA in human patients. In this study, multifunctional siRNA delivery nanoparticles are developed that combine imaging capability of nanoparticles with urokinase plasminogen activator receptor-targeted delivery of siRNA expressing DNA nanocassettes. This theranostic nanoparticle platform consists of a nanoparticle conjugated with targeting ligands and double-stranded DNA nanocassettes containing a U6 promoter and a shRNA gene for in vivo siRNA expression. Targeted delivery and gene silencing efficiency of firefly luciferase siRNA nanogenerators are demonstrated in tumor cells and in animal tumor models. Delivery of survivin siRNA expressing nanocassettes into tumor cells induces apoptotic cell death and sensitizes cells to chemotherapy drugs. The ability of expression of siRNAs from multiple nanocassettes conjugated to a single nanoparticle following receptor-mediated internalization should enhance the therapeutic effect of the siRNA-mediated cancer therapy.

Assessment of coronary microvascular dysfunction in hypertrophic cardiomyopathy: first-pass myocardial perfusion cardiovascular magnetic resonance imaging at 1.5 T

AIM

To evaluate the integrity of the coronary microvasculature in patients with hypertrophic cardiomyopathy (HCM) using first-pass magnetic resonance perfusion imaging.

MATERIALS AND METHODS

Twenty-two patients with HCM and 13 healthy volunteers underwent cardiac magnetic resonance imaging (CMR) at rest. Imaging protocols included short axis cine, first-pass myocardial perfusion, and late-phase contrast-enhanced imaging. Left ventricular end-diastolic wall thickness (EDTH), myocardial thickening, maximal upslope of time-intensity curve (slopemax), and late myocardial gadolinium enhancement (LGE) were assessed for each myocardial segment. The differences in slopemax, myocardial thickening, and EDTH between healthy volunteers and HCM patients were evaluated as were differences among hypertrophic segments of different severities (mild, moderate, and severe hypertrophy) in a one-way analysis of variance analysis. The differences in slopemax, myocardial thickening, and EDTH between the segments with and without LGE were compared by independent-sample t-test. A Pearson correlation test was used to determine the relationships between slopemax, EDTH, and myocardial thickening.

RESULTS

Slopemax was statistically significantly less in HCM patients; the degree of myocardial thickening was also significantly reduced (p < 0.001). Slopemax and the degree of thickening statistically significantly decreased with increasing degrees of myocardial hypertrophy (p < 0.05). Differences in slopemax, myocardial thickening, and EDTH were observed between segments with and without LGE (p < 0.05). Slopemax and myocardial thickening were negatively correlated with EDTH.

CONCLUSION

First-pass myocardial perfusion CMR with slopemax measurements demonstrates microvascular coronary dysfunction in patients with HCM, a determination that may aid in risk stratification, therapeutic planning, and determination of prognosis for HCM.

Synchronized signaling delivery for broadband 60 GHz in-building optical wireless network based on digital frequency division multiplexing and digital Nyquist shaping

A simple and low-cost synchronized signaling delivery scheme has been proposed for a 60 GHz in-building optical wireless network with 12.7Gbps throughput based on digital frequency division multiplexing and digital Nyquist shaping.

Anticandidal activity and biocompatibility of a rechargeable antifungal denture material

OBJECTIVES

Candida-associated denture stomatitis is a recurrent and debilitating oral mucosal disease. Development of anticandidal denture materials represents a promising strategy to manage this condition. We have previously shown that miconazole incorporated in methacrylic acid (MAA) copolymerized diurethane dimethacrylate (UDMA) denture materials has long-term anticandidal activity. In this study, we examined the ability of culture medium conditioned with drug-free- or miconazole-MAA-UDMA discs to prevent Candida infection in an in vitro oral epithelial cell/Candida albicans coculture system.

MATERIALS AND METHODS

Candida albicans (C. albicans)-induced OKF6/TERT-2 cell damage was quantified by the release of lactate dehydrogenase from epithelial cells, cytokine production was quantified using protein cytokine arrays, and the expression of C. albicans genes was measured by RT-qPCR.

RESULTS

Candida albicans had limited growth with altered expression levels of secreted aspartyl proteinase-2 and -5 in culture medium conditioned by miconazole-MAA-UDMA discs. Significantly, the ability of C. albicans to induce oral epithelial cell damage and trigger epithelial proinflammatory cytokine production was also inhibited by miconazole disc conditioned media.

CONCLUSION

Miconazole released from MAA-UDMA denture materials effectively prevents the development of candidal infection in an in vitro oral epithelial system. Further characterization of this drug-rechargeable denture material is warranted.

Combination of valproic acid and ATRA restores RARβ2 expression and induces differentiation in cervical cancer through the PI3K/Akt pathway

Epigenetic silencing of the tumor suppressor gene, RARβ2, through histone deacetylation has been established as an important process of cervical carcinogenesis. This pivotal role has led to the suggestion that a combination of retinoids selective for RARβ2 with histone deacetylase (HDAC) inhibitors may have therapeutic potential. Valproic acid (VPA), a HDAC inhibitor, has a critical role in the regulation of gene expression through histone acetylation and causes transformed cells to undergo growth arrest, differentiation, and apoptosis. Therefore, we hypothesized that the combination of VPA and ATRA could restore RARβ2 expression, thus resulting in enhanced anti-neoplastic activity in cervical cancer. Here, we show that VPA combined with ATRA led to hyperacetylation of histone H3 and a significant alteration of gene expression in cervical cancer cells, including RARβ2 gene expression, which was upregulated 50- to 90-fold. The combination therapy effectively inhibited the growth of cervical cancer cells more than the single agent treatment both in vitro and in vivo. The additive effects were associated with a significant upregulation of p21(CIP1) and p53 as well as a pronounced decrease in p-Stat3. Furthermore, the combined treatment led to cell cycle arrest predominantly at the G1 phase, and it preferentially induced cell differentiation rather than apoptosis in cervical cancer cells. The differentiation program was determined by the presence of E-cadherinmediated adhesion and activation of the PI3K/Akt pathway. Taken together, these results provide new insight into the mechanisms of enhanced antitumor activity of the HDAC inhibitor and ATRA regimen, thus offering a new therapeutic strategy for cervical cancer patients.

αA- and αB-crystallins interact with caspase-3 and Bax to guard mouse lens development

The small heat shock protein, α-crystallin, exists in two isoforms, αA and αB, and displays strong ability against stress-induced apoptosis. Regarding their functional mechanisms, we and others have demonstrated that they are able to regulate members in both caspase and Bcl-2 families. In addition, we have also shown that αA and αB may display differential anti-apoptotic mechanisms under certain stress conditions. While αA-crystallin regulates activation of the AKT signaling pathway, αB negatively regulates the MAPK pathway to suppress apoptosis induced by UV and oxidative stress. Although previous studies revealed that αA and αB could regulate members in both caspase and Bcl-2 families, the molecular mechanism, especially the in vivo regulation still waits to be elucidated. In the present communication, we present both in vitro and in vivo evidence to further demonstrate the regulation of caspase-3 and Bax by αA and αB. First, Surface Plasmon Resonance (SPR) and yeast two-hybrid selection analysis demonstrate that αA and αB directly bind to caspase-3 and Bax with differential affinities. Second, immunohistochemistry reveals that αA and αB regulate caspase-3 and Bax at different developmental stages of mouse embryo. Third, coimmunoprecipitation shows that αA and αB form in vivo interacting complexes with caspase-3 and Bax. Together, our results further confirm that αA and αB regulate caspase-3 and Bax in vitro and in vivo to regulate lens differentiation.

The amygdala is involved in affective priming effect for fearful faces

The object of this study was to investigate whether the amygdala is involved in affective priming effect after stimuli are encoded unconsciously and consciously. During the encoding phase, each masked face (fearful or neutral) was presented to participants six times for 17ms each, using a backward masking paradigm. During the retrieval phase, participants made a fearful/neutral judgment for each face. Half of the faces had the same valence as that seen during encoding (congruent condition) and the other half did not (incongruent condition). Participants were divided into unaware and aware groups based on their subjective and objective awareness assessments. The fMRI results showed that during encoding, the amygdala elicited stronger activation for fearful faces than neutral faces but differed in the hemisphere according to the awareness level. During retrieval, the amygdala showed a significant repetition priming effect, with the congruent faces producing less activation than the incongruent faces, especially for fearful faces. These data suggest that the amygdala is important in unconscious retrieving of memories for emotional faces whether they are encoded consciously or unconsciously.

Randomized clinical trial of laparoscopic anterior 180° partial versus 360° Nissen fundoplication: 5-year results

Anterior partial fundoplication (AF) has been popularized by a lower risk of mechanical side effects. The question then emerges whether anterior partial wrap has a similar antireflux effect with Nissen fundoplication (NF). We therefore conducted a randomized study to compare the long-term outcome of anterior fundoplication with NF. One hundred patients who enrolled in the trial from May 2003 to March 2005 were randomized to laparoscopic AF or laparoscopic NF. Endoscopy, pH monitoring, manometry, a detailed questionnaire, and a visual analog symptom score were completed preoperative at 6, 12, 24, and 60 months after surgical procedures. The postoperative adverse effects such as dysphagia and flatulence were compared between the two groups. Revision surgery or maintenance proton pump inhibitor therapy was defined as failure. Fifty procedures were performed in each group. The outcome at 5 years follow-up was determined for 96 patients (96%; 49 patients in the AF group and 47 in the NF group). Three patients (3%) died of unrelated causes during follow-up, and one patient changed address. Both fundoplications were found to provide good control of reflux-related symptoms in most of the patients. For 96 patients followed up more than 5 years, gastroesophageal reflux symptoms were well controlled in 81 patients (84.38%); the mean DeMeester scores in the AF group decreased from 106.89 ± 14.12 to 12.67 ± 3.14 and in the NF group from 109.51 ± 17.98 to 10.81 ± 2.65, and the esophagitis was ameliorated visibly. Moreover, there were significantly fewer patients in the AF group who complained of flatulence. Compared with NF, anterior 180° partial fundoplication is an effective treatment of gastroesophageal reflux and associates with fewer postoperative adverse effects.

Localized oblique-angle deposition: Ag nanorods on microstructured surfaces and their SERS characteristics

In this paper, we demonstrate a simple and convenient method of depositing Ag nanorods on a substrate inside a standard evaporation chamber with the substrate resting on a leveled stage. Microstructuring the substrate prior to the deposition imparts a large incidence angle (>70°) between the collimated vapor atoms and the local surface normal, which is essential to induce the shadowing effect. Thereby, a localized oblique-angle deposition (LOAD) is realized, forming nanorods selectively on the steep sidewalls of surface microcavities patterned via standard photolithography and silicon dry etching. We also demonstrate that these nanorods can boost SERS activity of the underlying substrate and thus perform comparable to those fabricated via advanced patterning techniques or conventional OAD whereby the entire substrate has to be tilted with respect to the incident vapor atoms. Our results suggest the viability of decorating microchannel sidewalls with SERS-active nanorods for integrated sample processing and SERS detection.

22q11.2 deletion presenting with severe hypocalcaemia, seizure and basal ganglia calcification in an adult man

We report a 40-year-old man who was found to have profound hypocalcaemia and hypoparathyroidism when investigated for multiple, generalized, tonic/clonic seizures and a chest infection. Computed tomography scan of the brain revealed extensive symmetric bilateral calcification within the cerebellum, thalamus and basal ganglia. Molecular cytogenetic testing by fluorescent in situ hybridization using the commercial Vysis LSI DiGeorge/VCFS dual colour probe set showed a deletion of 22q11.2. The extraordinary feature of this case is the adult presentation of hypocalcaemia, hypoparathyroidism and basal ganglia calcification due to 22q11.2 deletion.

Responses of bone-forming cells on pre-immersed Zr-based bulk metallic glasses: Effects of composition and roughness

Bulk metallic glasses (BMGs) demonstrate attractive properties for potential biomedical applications, owing to their amorphous structure. The present work has investigated the biocompatibility of Zr-based BMGs by studying the cellular behavior of bone-forming mouse MC3T3-E1 pre-osteoblast cells. A Ti-6Al-4V alloy was used as a reference material. Pre-immersion treatment was performed on BMG samples in phosphate-buffered saline prior to cell experiments. The effects of 1at.% yttrium alloying and surface roughness on cellular behavior were examined. The general biosafety of Zr-based BMGs for MC3T3-E1 cells was revealed as normal cell responses. Pre-immersion treatment was found to effectively reduce the surface concentrations of alloying elements. Micro-alloying with 1 at.% yttrium did not significantly affect cell adhesion and proliferation, but slightly decreased alkaline phosphatase (ALP) activity on rough surfaces. Lower cell adhesion and proliferation were found on smooth surfaces of Zr-based BMGs compared to their rougher counterparts. Higher ALP activity was detected on rougher surfaces. To obtain a mechanistic understanding surface free energy was correlated with cell adhesion.

Rechargeable infection-responsive antifungal denture materials

Candida-associated denture stomatitis (CADS) is a significant clinical concern. We developed rechargeable infection-responsive antifungal denture materials for potentially managing the disease. Polymethacrylic acid (PMAA) was covalently bound onto diurethane dimethacrylate denture resins in the curing step. The PMAA resins bound cationic antifungal drugs such as miconazole and chlorhexidine digluconate (CG) through ionic interactions. The anticandidal activities of the drug-containing PMAA-resin discs were sustained for a prolonged period of time (weeks and months). Drug release was much faster at acidic conditions (pH 5) than at pH 7. Drugs bound to the denture materials could be "washed out" by treatment with EDTA, and the drug-depleted resins could be recharged with the same or a different class of anticandidal drugs. These results suggest clinical potential of the newly developed antifungal denture materials in the management of CADS and other infectious conditions.

Antimicrobial peptides expression by ocular surface cells in response to Acanthamoeba castellanii: an in vitro study

AIMS

Antimicrobial peptides (AMPs) are natural effectors of the innate immune response. Much work has been done to study their response and effects on bacterial and viral infection. Little if any information is available in relation to protozoal infections. The aim of the study was to comprehensively study the gene expression of the ocular AMPs in human corneal limbal epithelial cells stimulated with Acanthamoeba castellanii (AC).

METHODS

Human corneal limbal epithelial cells were exposed to AC at different time points, up to 9 h, the genomic profile of the AMPs were analysed at these time point using real time PCR. corneal limbal epithelial cells not infected with AC were used as controls.

RESULTS

Seven of the eight studied AMPs showed statistically significant upregulation in gene expression. Human beta Defensin 3 (hBD3) showed a very significant 10-fold upregulation in the exposed cells and Ribonuclease-7 (RNase-7) showed a very early and consistent increase. Human beta Defensin 1 (hBD1) was the only downregulated AMP.

CONCLUSIONS

The study data suggests a possible role of the AMPs in combating the amoebic infection at the ocular surface. Using AMPs singly or in combination is a promising avenue for further exploration in the treatment of the sight threatening Acanthamoeba keratitis.

Pharmacological inhibition of the mammalian target of rapamycin pathway suppresses acquired epilepsy

Inhibition of mTOR by rapamycin has been shown to suppress seizures in TSC/PTEN genetic models. Rapamycin, when applied immediately before or after a neurological insult, also prevents the development of spontaneous recurrent seizures (epileptogenesis) in an acquired model. In the present study, we examined the mTOR pathway in rats that had already developed chronic spontaneous seizures in a pilocarpine model. We found that mTOR is aberrantly activated in brain tissues from rats with chronic seizures. Furthermore, inhibition of mTOR by rapamycin treatment significantly reduces seizure activity. Finally, mTOR inhibition also significantly suppresses mossy fiber sprouting. Our findings suggest the possibility for a much broader window for intervention for some acquired epilepsies by targeting the mTOR pathway.

Indications of proton-dominated cosmic-ray composition above 1.6 EeV

We report studies of ultrahigh-energy cosmic-ray composition via analysis of depth of air shower maximum (X(max)), for air shower events collected by the High-Resolution Fly's Eye (HiRes) observatory. The HiRes data are consistent with a constant elongation rate d<X(max)>/d[log(E)] of 47.9+/-6.0(stat)+/-3.2(syst) g/cm2/decade for energies between 1.6 and 63 EeV, and are consistent with a predominantly protonic composition of cosmic rays when interpreted via the QGSJET01 and QGSJET-II high-energy hadronic interaction models. These measurements constrain models in which the galactic-to-extragalactic transition is the cause of the energy spectrum ankle at 4x10(18) eV.

The temporal expression and localization of extracellular matrix metalloproteinase inducer (EMMPRIN) during the development of periodontitis in an animal model

BACKGROUND AND OBJECTIVE

We previously demonstrated extracellular matrix metalloproteinase inducer (EMMPRIN) was associated with the matrix metalloproteinases production of human periodontitis. The aim of this study was to investigate the temporal expression and localization of EMMPRIN during ligature-induced periodontitis in rats.

MATERIAL AND METHODS

Periodontitis was induced in rats by placing a thread around the cervix of the first mandibular molar. Animals were killed 3, 7, 11, 15 or 21 d after ligation. Mandibles were processed for paraffin sections and stained with hematoxylin and eosin or picrosirius red. The distance from the amelocemental junction to the alveolar crest (ACJ-AC) and the area fraction (Area%) of collagen fibers were measured. EMMPRIN was examined by immunohistochemistry and quantified by positive cell counting. Correlation analyses were then performed.

RESULTS

Histologically, alveolar bone was gradually destroyed from day 3 to 11 and then stabilized. Collagen fibers were slightly dissociated on day 3 and extensively broken on day 7. They were reconstructed from day 11 to 21. EMMPRIN was localized predominantly in infiltrating cells and adjacent fibroblasts in interdental gingiva. The number of EMMPRIN-positive cells increased on day 3, peaked on day 7 and then gradually subsided from day 11 to 21. Statistically, there was a moderate positive correlation regarding the ACJ-AC distance (r = 0.552, p < 0.01) and a strong negative correlation with the Area% of collagen fibers (r = -0.808, p < 0.01). In gingival epithelium, the immunoreactivity was extremely strong in basal layer cells and sulcular epithelial cells in health. It was greatly enhanced in the inflamed conditions on days 3 and 7. In the interradicular bone, EMMPRIN was localized in the osteoclasts on days 3 and 7, as well as in the osteoblasts from day 11 onwards.

CONCLUSION

The expression and localization of EMMPRIN are temporally varied during the development of periodontitis. In addition, the inflammation-dependent expression of EMMPRIN might be involved in alveolar bone resorption and collagen breakdown.

AKT1 polymorphisms are associated with tuberculosis in the Chinese population

AKT1, a serine/threonine kinase, plays a critical role in the controlling of intracellular growth of Mycobacterium tuberculosis. In this study, we investigated whether polymorphisms in AKT1 affect susceptibility to tuberculosis (TB). Two single nucleotide polymorphisms of AKT1, IVS3+18C>T and +726G>A were genotyped in Chinese patients with pulmonary TB by polymerase chain reaction-restriction fragment length polymorphism. Patients with pulmonary TB had significantly lower IVS3+18 C/C genotype and higher C/T genotype compared with age-, gender- and ethnically matched controls (P < 0.05). The T-A haplotype frequency was significantly higher in patients than in controls (P < 0.05). In conclusion, our result indicates that AKT1 polymorphisms are associated with susceptibility to pulmonary TB.

Angiotensin II subtype 2 receptor blockade and deficiency attenuate the development of atherosclerosis in an apolipoprotein E-deficient mouse model of diabetes

AIMS/HYPOTHESIS

Most of the known actions of angiotensin II have been considered primarily to be the result of angiotensin II subtype 1 receptor activation. However, recent data suggest that the angiotensin II subtype 2 receptor (AT(2)R) may modulate key processes linked to atherosclerosis. The aim of this study was to investigate the role of AT(2)R in diabetes-associated atherosclerosis using pharmacological blockade and genetic deficiency.

METHODS

Aortic plaque deposition was assessed in streptozotocin-induced diabetic apolipoprotein E (Apoe) knockout (KO) and At ( 2 ) r (also known as Agtr2)/Apoe double-KO (DKO) mice. Control and diabetic Apoe-KO mice received an AT(2)R antagonist PD123319 (5 mg kg(-1) day(-1)) via osmotic minipump for 20 weeks (n = 7-8 per group).

RESULTS

Diabetes was associated with a sixfold increase in plaque area (diabetic Apoe-KO: 12.7 +/- 1.4% vs control Apoe-KO: 2.3 +/- 0.4%, p < 0.001) as well as a significant increase in aortic expression of the gene At ( 2 ) r (also known as Agtr2). The increase in plaque area with diabetes was attenuated in AT(2)R antagonist-treated diabetic Apoe-KO mice (7.1 +/- 0.5%, p < 0.05) and in diabetic At ( 2 ) r/Apoe DKO mice (9.2 +/- 1.3%, p < 0.05). These benefits occurred independently of glycaemic control or BP, and were associated with downregulation of a range of pro-inflammatory cytokines, adhesion molecules, chemokines and various extracellular matrix proteins.

CONCLUSIONS/INTERPRETATION

This study provides evidence for AT(2)R playing a role in the development of diabetes-associated atherosclerosis. These findings suggest a potential utility of AT(2)R blockers in the prevention and treatment of diabetic macrovascular complications.

Fire ant alate wing motion data and numerical reconstruction

The wing motions of a male and a female fire ant alate, which beat their wings at 108 and 96 Hz, respectively, were captured with a stereo imaging system at a high frame rate of 8,000 frames per second. By processing the high-speed image frames, the three-dimensional wingtip positions and the wing surface orientation angles were determined with a high phase resolution, i.e. 74 and 83 phases per period for the male and the female, respectively. A numerical reconstruction of the stereo wingbeat images demonstrated that the data collected described almost all the details of the wing surface motion, so that further computational fluid dynamic simulations are possible for fire ant alate flight.

Cell division autoantigen 1 plays a profibrotic role by modulating downstream signalling of TGF-beta in a murine diabetic model of atherosclerosis

AIMS/HYPOTHESIS

Excess accumulation of vascular extracellular matrix (ECM) is an important pathological process in cardiovascular diseases including diabetes-associated atherosclerosis. We explored how a recently identified molecule, cell division autoantigen 1 (CDA1), influences the profibrotic TGF-beta pathway leading to vascular ECM accumulation.

METHODS

Expression levels of genes encoding for CDA1, TGF-beta and connective tissue growth factor (CTGF) were examined in aorta from Apoe(-/-) mice with or without diabetes. We used retroviral and adenoviral constructs to knockdown or overexpress Tspyl2, the gene encoding CDA1, in mouse vascular smooth muscle cells (VSMCs) with or without TGF-beta treatment in order to demonstrate the role of CDA1 in TGF-beta signalling.

RESULTS

In vivo studies indicated that the mRNA levels of CDA1-encoding gene Tspyl2 and protein levels of CDA1 were elevated in the aorta of diabetic Apoe(-/-) mice, accompanied by increased levels of Tgf-beta (also known as Tgfb1), Ctgf and ECM accumulation. In vitro studies in vascular cells showed that TGF-beta treatment rapidly increased CDA1 protein levels, which then amplified TGF-beta signalling leading to upregulation of ECM genes. Knockdown of CDA1-encoding gene Tspyl2 to reduce cellular CDA1 level markedly attenuated TGF-beta-stimulated MAD homologue 3 (drosophila; SMAD3) phosphorylation and transcriptional activities. CDA1 overproduction increased and Tspyl2 knockdown decreased expression of TGF-beta receptor type I, TbetarI (also known as Tgfbr1), but not TGF-beta receptor type II, TbetarII (also known as Tgfbr2), providing a mechanism for CDA1's action in modulating TGF-beta signalling. Knockdown of CDA1-encoding gene Tspyl2 also blocked the profibrotic effect of TGF-beta in VSMCs.

CONCLUSIONS/INTERPRETATION

CDA1 plays an important role in vascular ECM accumulation by amplifying TGF-beta signalling. This is critical for the profibrotic effect of TGF-beta in the vasculature. CDA1 is therefore a potential target for attenuating vascular ECM accumulation caused by enhanced TGF-beta action, as seen in diabetic atherosclerosis.

The Glu346Lys polymorphism and frameshift mutations of the Methyl-CpG Binding Domain 4 gene in gastrointestinal cancer

MBD4 (Methyl-CpG Binding Domain 4) is a human DNA repair protein that may be involved in DNA mismatch repair. The polymorphisms and frameshift mutations in MBD4 may influence cancer susceptibility and the development of cancer. The specific aim of this study was to investigate whether frameshift mutations of the MBD4 gene and the codon 346 polymorphism were associated with microsatellite instability (MSI) and the risk for gastrointestinal cancer. We examined the MSI, frameshift mutations and polymorphisms of the MBD4 gene in 84 patients with gastric cancers, 82 colorectal cancers and 299 healthy controls. MSI was found in 19 (22.6%) and 26 (31.7%) of the gastric and colorectal cancer samples, respectively. The mutation analysis revealed no frameshift mutations in the MBD4 gene among the gastrointestinal cancers. The frequencies of genotypes: Glu/Glu, Glu/Lys and Lys/Lys were 41.7% (35/84), 41.7% (35/84) and 16.6% (14/84), respectively, in the gastric cancer cases, and 42.7% (35/82), 36.6% (30/82) and 20.7% (17/82), respectively, in the colorectal cancers. MSI was not associated with the MBD4 codon 346 polymorphism and there was no significant difference in the frequency of the genotypes between healthy controls and gastric cancer patients (P=0.2748). However, the MBD4 codon 346 polymorphism was significantly associated with the risk of colorectal cancer (P=0.0315). Our findings suggest that microsatellite instability may not be associated with frameshift mutations in the MBD4 gene, and that the MBD4 codon 346 polymorphism may play arole in colorectal cancer susceptibility in the Korean population.

A muscle-targeting peptide displayed on AAV2 improves muscle tropism on systemic delivery

Adeno-associated virus (AAV) has become a leading gene transfer vector for striated muscles. However, the AAV vectors also exhibit broad tropisms after systemic delivery. In an attempt to improve muscle tropism, we inserted a 7-amino-acid (ASSLNIA) muscle-targeting peptide (MTP) in the capsids of AAV2 at residue 587 or 588, generating AAV₅₈₇MTP and AAV₅₈₈MTP. In vitro studies showed that both viruses diminished their infectivity on non-muscle cell lines as well as on un-differentiated myoblasts, however, preserved or enhanced their infectivity on differentiated myotubes. AAV₅₈₇MTP, but not AAV₅₈₈MTP, also abolished its heparin-binding capacity and infected myotubes in a heparin-independent manner. Furthermore, in vivo studies by intravenous vector administration in mice showed that AAV₅₈₇MTP enhanced its tropism to various muscles and particularly to the heart (24.3 fold of unmodified AAV2), whereas reduced its tropism to the non-muscle tissues such as the liver, lungs and spleen, etc. This alteration of tissue tropism is not simply due to the loss of heparin-binding, since a mutant AAV2 (AAVHBSMut) containing heparin-binding site mutations lost infectivity on both non-muscle and muscle cells. Furthermore, free MTP peptide, but not the scrambled control peptide, competitively inhibited AAV₅₈₇MTP infection on myotubes. These results suggest that AAV2 could be re-targeted to the striated muscles by a muscle-targeting peptide inserted after residue 587 of the capsids. This proof of principle study showed first evidence of peptide-directed muscle targeting upon systemic administration of AAV vectors.

The p53 codon 72 polymorphism and susceptibility to colorectal cancer in Korean patients

TP53 is a major gene involved in the determination of proliferation or growth arrest at the cellular level. The polymorphism of p53 at codon 72 has been widely studied; this variation has been associated with cancer susceptibility and disease outcome. The specific aim of this study was to investigate whether the p53 codon 72 polymorphism is associated with individual susceptibility to colorectal cancer in Korean patients. The frequency of the polymorphism was examined in 156 patients with colorectal cancer and in 293 healthy controls. The polymorphism analysis was performed by amplifying exon 4 of p53 and digesting the products with restriction enzyme. The frequencies of genotypes: Arg/Arg, Arg/Pro and Pro/Pro were 34.6% (54/156), 43.0% (67/156) and 22.4% (35/156), respectively, in the cases with colorectal cancer, and 28.9% (114/293), 47.8% (140/293) and 13.3% (39/293), respectively, in the healthy controls. Statistically, there was a significant difference in the frequency of the genotypes when the healthy controls were compared to the patients with colorectal cancer (<em>p</em>=0.0459). The specific allele frequencies showed borderline significance (<em>p</em>=0.0502). Our findings suggest that the p53 Pro72 variant is associated with an increased risk for colorectal cancer in the Korean population.

KEYWORDS

p53, colorectal cancer, polymorphism, susceptibility, metastasis.

Multifunctional and multiplexed nanoparticles for molecular imaging and treatment of breast cancer

Abstract #6003

Multifunctional nanoparticles with the ability to target tumors, provide molecular imaging and to deliver therapeutic agents hold great promise for improving the survival of cancer patients. We have developed multifunctional nanoparticles targeted to cellular receptors that are highly expressed in breast cancer and tumor stromal cells. Fluorescent quantum dot (QD) or magnetic iron oxide (IO) nanoparticles are conjugated to either the amino-terminal fragment (ATF) of urokinase plasminogen activator (uPA) or to a single chain antibody against the epidermal growth factor receptor (ScFvEGFR), resulting in uPAR or EGFR targeted nanoparticles. Since the binding of ATF peptides or ScFvEGFR to their receptors results in blocking receptor function and internalization of the receptor-ligand complex, these targeted imaging probes can also inhibit tumor growth and deliver drugs. Using near infrared fluorescence (NIR) dye-labeled targeting peptides, we demonstrate specificity of these targeting ligands in an orthotopic human breast cancer model in nude mice. We found that tail vein injection of a mixture of Cy5.5 dye-ATF and IRDye 800-ScFvEGFR peptides leads to the selective accumulation of both probes in human breast cancer xenografts and NIR optical imaging of the tumors in the mammary fat pad of nude mice (Fig. A).&#x2028; &#x2028; We show that uPAR- and EGFR-targeted nanoprobes display different patterns of intratumoral distribution with EGFR probes in the central area and uPAR probes in the peripheral and central regions of the tumor, which may be the results of expressing uPAR in the invasive edge of tumor cells and tumor stromal cells and EGFR only in tumor cells. In vivo optical imaging using ATF-nanoparticles is also demonstrated in human breast cancer xenograft (Fig. B) and in mouse mammary tumor lung metastatic models. Furthermore, magnetic Cy5.5-ATF IO nanoparticles are multimodality imaging probes for both optical and MR tumor imaging. Since magnetic IO nanoparticles are biodegradable and relatively safe for human use, we have developed a therapeutic imaging nanoparticle by encapsulating doxorubicin into the polymer coating of the nanoparticles and have shown selective delivery of the drug and cytotoxic effect in breast cancer cells in vitro. Results of our study show that multifunctional and multiplexed nanoparticles have great potential for the development of novel tumor imaging and therapeutic approaches.

Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 6003.

MAST3: a novel IBD risk factor that modulates TLR4 signaling

Inflammatory bowel disease (IBD) is a chronic disorder caused by multiple factors in a genetically susceptible host. Significant advances in the study of genetic susceptibility have highlighted the importance of the innate immune system in this disease. We previously completed a genome-wide linkage study and found a significant locus (IBD6) on chromosome 19p. We were interested in identifying the causal variant in IBD6. We performed a two-stage association mapping study. In stage 1, 1530 single-nucleotide polymorphisms (SNPs) were selected from the HapMap database and genotyped in 761 patients with IBD. Among the SNPs that passed the threshold for replication, 26 were successfully genotyped in 754 additional patients (stage 2). One intronic variant, rs273506, located in the microtubule-associated serine/threonine-protein kinase gene-3 (MAST3), was found to be associated in both stages (pooled P=1.8 x 10(-4)). We identified four MAST3 coding variants, including a non-synonymous SNP rs8108738, correlated to rs273506 and associated with IBD. To test whether MAST3 was expressed in cells of interest, we performed expression assays, which showed abundant expression of MAST3 in antigen-presenting cells and in lymphocytes. The knockdown of MAST3 specifically decreased Toll-like receptor-4-dependent NF-kappaB activity. Our findings are additional proofs of the pivotal role played by modulators of NF-kappaB activity in IBD pathogenesis.

First observation of the Greisen-Zatsepin-Kuzmin suppression

The High Resolution Fly's Eye (HiRes) experiment has observed the Greisen-Zatsepin-Kuzmin suppression (called the GZK cutoff) with a statistical significance of five standard deviations. HiRes' measurement of the flux of ultrahigh energy cosmic rays shows a sharp suppression at an energy of 6 x 10(19) eV, consistent with the expected cutoff energy. We observe the ankle of the cosmic-ray energy spectrum as well, at an energy of 4 x 10(18) eV. We describe the experiment, data collection, and analysis and estimate the systematic uncertainties. The results are presented and the calculation of the statistical significance of our observation is described.

Down-regulation of ATBF1 is a major inactivating mechanism in hepatocellular carcinoma

AIMS

alpha-Fetoprotein (AFP) is frequently detected in hepatocellular carcinomas (HCCs) and AT motif binding factor 1 (ATBF1) down-regulates AFP gene expression in hepatic cells. The ATBF1 gene also inhibits cell growth and differentiation, and altered gene expression is associated with malignant transformation. The aim was to investigate the potential role of the ATBF1 gene in HCCs.

METHODS AND RESULTS

Somatic mutations, allelic loss and hypermethylation of the ATBF1 gene were analysed in 76 sporadic HCCs. The level of ATBF-1 mRNA expression was analysed using quantitative real-time reverse transcriptase-polymerase chain reaction. Genetic studies of the ATBF1 gene revealed absence of somatic mutation in the hotspot region and 15 (25%) of 60 informative cases showed allelic loss at the ATBF1 locus. Hypermethylation in the intron 1 region of the ATBF1 gene was detected in only one case. Interestingly, ATBF1 mRNA expression in HCCs was significantly reduced in 55 (72.4%) samples compared with the corresponding surrounding liver tissues. Reduced expression was not statistically associated with clinicopathological parameters including stage, histological grade, infective virus type, and serum alpha-fetoprotein level.

CONCLUSIONS

The ATBF1 gene may contribute to the development of HCCs via transcriptional down-regulation of mRNA expression, but not by genetic or epigenetic alterations.

A blue light inducible two-component signal transduction system in the plant pathogen Pseudomonas syringae pv. tomato

The open reading frame PSPTO2896 from the plant pathogen Pseudomonas syringae pv. tomato encodes a protein of 534 amino acids showing all salient features of a blue light-driven two-component system. The N-terminal LOV (light, oxygen, voltage) domain, potentially binding a flavin chromophore, is followed by a histidine kinase (HK) motif and a response regulator (RR). The full-length protein (PST-LOV) and, separately, the RR and the LOV+HK part (PST-LOV(DeltaRR)) were heterologously expressed and functionally characterized. The two LOV proteins showed typical LOV-like spectra and photochemical reactions, with the blue light-driven, reversible formation of a covalent flavin-cysteine bond. The fluorescence changes in the lit state of full-length PST-LOV, but not in PST-LOV(DeltaRR), indicating a direct interaction between the LOV core and the RR module. Experiments performed with radioactive ATP uncover the light-driven kinase activity. For both PST-LOV and PST-LOV(DeltaRR), much more radioactivity is incorporated when the protein is in the lit state. Furthermore, addition of the RR domain to the fully phosphorylated PST-LOV(DeltaRR) leads to a very fast transfer of radioactivity, indicating a highly efficient HK activity and a tight interaction between PST-LOV(DeltaRR) and RR, possibly facilitated by the LOV core itself.

No association of MDM2 T309G polymorphism with susceptibility to Korean gastric cancer patients

Mouse double minute 2 (Mdm2) acts as a negative regulator of p53 by binding to the amino-terminus of p53. The common T309G polymorphism of Mdm2 has been the most frequently investigated, which can influence in cancer susceptibility and disease outcome. The specific aim of this study is to investigate whether the T309G polymorphism of Mdm2 was associated with individual susceptibility to gastric cancer in Korea. The frequency of the polymorphism was examined in 239 gastric cancer patients and 299 healthy controls. Polymorphism analysis was performed by amplifying the first intron of the Mdm2 and digesting with restriction enzyme and sequencing the products. The frequencies of genotypes: T/T, T/G and G/G were 26.8% (64/239), 46.0% (110/239) and 27.2% (65/239), respectively, in gastric cancer cases and 20.4% (61/299), 50.8% (152/ 299) and 28.8% (86/299), respectively, in healthy controls. Statistically, there was no significant difference in the frequency of genotype and allele between healthy control and gastric cancer patients. Finally, the polymorphism was not associated with increased risk of gastric cancer in this population. When stratified by histological subtype of gastric cancer, the risk was also not statistically significant. Our findings suggested that the T309G polymorphism of Mdm2 was not associated with an increased risk for gastric cancer in Korean population.