Precision measurement of the neutron twist-3 matrix element d(2)(n): probing color forces

Double-spin asymmetries and absolute cross sections were measured at large Bjorken x  (0.25≤x≤0.90), in both the deep-inelastic and resonance regions, by scattering longitudinally polarized electrons at beam energies of 4.7 and 5.9 GeV from a transversely and longitudinally polarized (3)He target. In this dedicated experiment, the spin structure function g(2)((3)He) was determined with precision at large x, and the neutron twist-3 matrix element d(2)(n) was measured at ⟨Q(2)⟩ of 3.21 and 4.32  GeV(2)/c(2), with an absolute precision of about 10(-5). Our results are found to be in agreement with lattice QCD calculations and resolve the disagreement found with previous data at ⟨Q(2)⟩=5  GeV(2)/c(2). Combining d(2)(n) and a newly extracted twist-4 matrix element f(2)(n), the average neutron color electric and magnetic forces were extracted and found to be of opposite sign and about 30  MeV/fm in magnitude.

Measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the reaction (3)He(↑)(e,e')X

We report the first measurement of the target-normal single-spin asymmetry in deep-inelastic scattering from the inclusive reaction 3)He(↑)(e,e')X on a polarized (3)He gas target. Assuming time-reversal invariance, this asymmetry is strictly zero in the Born approximation but can be nonzero if two-photon-exchange contributions are included. The experiment, conducted at Jefferson Lab using a 5.89 GeV electron beam, covers a range of 1.7<W<2.9  GeV, 1.0<Q(2)<4.0  GeV(2) and 0.16<x<0.65. Neutron asymmetries were extracted using the effective nucleon polarization and measured proton-to-(3)He cross-section ratios. The measured neutron asymmetries are negative with an average value of (-1.09±0.38)×10(-2) for invariant mass W>2  GeV, which is nonzero at the 2.89σ level. Our measured asymmetry agrees both in sign and magnitude with a two-photon-exchange model prediction that uses input from the Sivers transverse momentum distribution obtained from semi-inclusive deep-inelastic scattering.

Role of Ku70 in deubiquitination of Mcl-1 and suppression of apoptosis

Mcl-1 is a unique antiapoptotic Bcl2 family member with a short half-life due to its rapid turnover through ubiquitination. We discovered that Ku70, a DNA double-strand break repair protein, functions as a deubiquitinase to stabilize Mcl-1. Ku70 knockout in mouse embryonic fibroblast (MEF) cells or depletion from human lung cancer H1299 cells leads to the accumulation of polyubiquitinated Mcl-1 and a reduction in its half-life and protein expression. Conversely, expression of exogenous Ku70 in Ku70(-/-) MEF cells restores Mcl-1 expression. Subcellular fractionation indicates that Ku70 extensively colocalizes with Mcl-1 in mitochondria, endoplasmic reticulum and nucleus in H1299 cells. Ku70 directly interacts with Mcl-1 via its C terminus (that is, aa 536-609), which is required and sufficient for deubiquitination and stabilization of Mcl-1, leading to suppression of apoptosis. Purified Ku70 protein directly deubiquitinates Mcl-1 by removing K48-linked polyubiquitin chains. Ku70 knockdown not only promotes Mcl-1 turnover but also enhances antitumor efficacy of the BH3-mimetic ABT-737 in human lung cancer xenografts. These findings identify Ku70 as a novel Mcl-1 deubiquitinase that could be a potential target for cancer therapy by manipulating Mcl-1 deubiquitination.

Whole-Genome Sequence of "Candidatus Liberibacter asiaticus" from Guangdong, China

The draft genome sequence of "Candidatus Liberibacter asiaticus" strain A4, isolated from a mandarin citrus in Guangdong, People's Republic of China, is reported. The A4 strain has a genome size of 1,208,625 bp, G+C content of 36.4%, 1,107 predicted open reading frames, and 53 RNA genes.

Population Structures of 'Candidatus Liberibacter asiaticus' in Southern China

Huanglongbing (HLB) is a highly detrimental citrus disease associated with 'Candidatus Liberibacter asiaticus', a nonculturable alpha-proteobacterium. Characterization of the bacterial populations is important for development of disease management strategies. In this study, the 'Ca. L. asiaticus' populations in eight provinces in southern China where HLB is endemic were analyzed based on tandem repeat number (TRN) variations in a previously characterized genomic locus CLIBASIA_01645. Of the 224 HLB samples collected, 175 (78.3%) samples yielded single polymerase chain reaction (PCR) amplicons (the single amplicon group, SAG) and 49 (21.7%) samples produced multiple PCR amplicons (the multiple amplicon group, MAG). Variations in SAG are summarized by Nei's diversity index (H) and ratio of TRN ≤ 10/TRN > 10 genotypes (R10). Variations in the MAG are described by the percentage of occurrence (PMAG). At an orchard-level comparison, the 'Ca. L. asiaticus' population from a Guangdong orchard (n = 24) showed H = 0.50, R10 = 23, and PMAG = 0, significantly different from that of the non-Guangdong orchards in Yunnan (n = 23), H = 0.83, R10 = 2.3, and PMAG = 11.5, and in Hainan (n = 35), H = 0.88, R10 = 1.5, and PMAG = 16.7. In a region-level consideration, the Guangdong 'Ca. L. asiaticus' population (n = 78) was H = 0.77, R10 = 25, and PMAG = 1.3, whereas the non-Guangdong population (n = 84) was H = 0.91, R10 = 1.6, and PMAG = 26.9. Overall, significant differences were observed between the 'Ca. L. asiaticus' population from Guangdong Province and those from the other provinces. A strong aggregation of TRN = 6, 7, and 8 genotypes is characteristic to the 'Ca. L. asiaticus' population in Guangdong. Referenced to genome annotation, we propose that rearrangement of tandem repeats at locus CLIBASIA_01645 could be associated with bacterial environmental adaptation.

Abstract P4-16-07: Mesenchymal-epithelial transition (MET) and epithelial-mesenchymal transition (EMT) are closely related to chemotherapy resistance of triple negative breast cancer

Triple negative breast cancer (TNBC) is among the most aggressive clinical phenotypes and the presence of residual resistant cancer cells of TNBC after chemotherapy is associated with tumor recurrence and metastasis. In recent years more and more evidence highlight a crucial role of CD44 (+)/CD24 (-/low) (stem/progenitor cell-phenotype) population in cancer drug resistance but the mechanism remains elusive. In the current study, we screened for CD44 and CD24 using Fluorescence-activated cell sorting (FACS) in 8 TNBC cell lines before and after Docetaxel and Doxorubicin treatment. Our data showed that after Docetaxel treatment, several CD44 (+)/CD24 (-/low) cell lines changed their phenotypes to CD44 (+)/CD24 (+) and most of the CD44 (+)/CD24 (+) cell lines kept their double positive phenotypes. In contrast, after Doxorubicin treatment, all the CD44 (+)/CD24 (-/low) cell lines kept their phenotypes and all the CD44 (+)/CD24 (+) cell lines changed their phenotypes to CD44 (+)/CD24 (-/low). Furthermore, among the studied 8 cell lines, CD44 (+)/CD24 (+) cell population is always more resistant to Docetaxel and CD44 (+)/CD24 (-/low) population is always more resistant to Doxorubicin. Our finding of EMT transition from CD44 (+)/CD24 (+) to CD44 (+)/CD24 (-/low) in breast cancer cell lines and its inducible by Doxorubicin is consistent with the literature. However, our results showed for the first time that both EMT and the inverse MET in TNBC could be induced by specific chemotherapy drugs based on the phenotypes of CD44 and CD24. Besides, our gene microarray data also showed that TGFb2, BCL2, KLF6 and TAF4 pathways were dramatically changed in both CD44 (+)/CD24 (+) to CD44 (+)/CD24 (-/low) transition and CD44 (+)/CD24 (-/low) to CD44 (+)/CD24 (+) transition. Further study of these pathways in the transitions may give us new clues to overcome the chemotherapy resistance and lead us to develop successful therapeutic strategies of different types of TNBC.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-16-07.

Abstract P5-03-12: Prognostic role of stem cell markers in triple-negative breast cancer (TNBC)

Introduction: Triple-negative breast cancer (TNBC) is among the most aggressive types of breast cancer with frequent recurrence and death despite chemotherapy. Studies have shown that cancer stem cells play a key role in many of the drug resistant cancers including TNBC. In this study, we report the expressions of four stem cell markers in 158 TNBC tumors.

Design: Clinicopathological data were obtained from 158 triple negative breast cancers between 2002 and 2010. Tissue microarray was constructed and immunohistochemistry stains (IHC) for CD44 and CD24, CD 133 and ALDH1 were performed using the streptavidin-biotin method. Each set of TNBC consists of normal, ductal carcinoma in situ and invasive areas for assessment of IHC stains. Statistical analysis was done on the following parameters: Histological types, modified Bloom and Richardson grades, lymph-vascular invasion, lymph node status, tumor size, Ki67, presence of lymphocytic host response, age &gt;50 or &lt;50, BRCA status, prognosis (recurrence and death) and chemotherapeutic response. P values less than 0.05 were considered statistically significant.

Results: the mean age of this cohort of TNBC patients was 55 with 64% white, 13.2% black, 12.6% Asian/Pacific, 3.8% Hispanic/Latino and 1.9% other. The majority of these tumors (82.3%) were grade 3, 15.2% were grade 2, and less than 1% was grade 1. CD24, CD44 and CD133 expressions were significantly higher in TNBC than in normal breast tissues (p = 5.53 e-10, p = 1.14 e-11, p = 2.25 e-08 respectively). While both CD24 and CD133 expressions predicted poor survival (p = 0.073 and p = 0.043 respectively), neither was associated with recurrence. In contrast to CD24, CD44 and CD133 expressions, ALDH-1 expression was rare in TNBC and surrounding normal tissues. When expressed, ALDH-1 was associated with poor survival but cases were too few to reach significance. None of the four stem cell markers studied were associated with any of the conventional histopathologic features and BRCA1 or BRCA2 mutations.

Conclusions: Our study suggests that stem cell marker(s) may be prognostically important in TNBC patients. When it is fully characterized it may provide new insight in developing effective therapeutic strategies targeting stem cell related signaling pathways.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P5-03-12.

Measurements of parity-violating asymmetries in electron-deuteron scattering in the nucleon resonance region

We report on parity-violating asymmetries in the nucleon resonance region measured using inclusive inelastic scattering of 5-6 GeV longitudinally polarized electrons off an unpolarized deuterium target. These results are the first parity-violating asymmetry data in the resonance region beyond the Δ(1232). They provide a verification of quark-hadron duality-the equivalence of the quark- and hadron-based pictures of the nucleon-at the (10-15)% level in this electroweak observable, which is dominated by contributions from the nucleon electroweak γZ interference structure functions. In addition, the results provide constraints on nucleon resonance models relevant for calculating background corrections to elastic parity-violating electron scattering measurements.

A triple suicide gene strategy that improves therapeutic effects and incorporates multimodality molecular imaging for monitoring gene functions

Gene-directed enzyme prodrug therapy (GDEPT), or suicide gene therapy, has shown promise in clinical trials. In this preclinical study using stable cell lines and xenograft tumor models, we show that a triple-suicide-gene GDEPT approach produce enhanced therapeutic efficacy over previous methods. Importantly, all the three genes (thymidine kinase, cytosine deaminase and uracil phosphoribosyltransferase) function simultaneously as effectors for GDEPT and markers for multimodality molecular imaging (MMI), using positron emission tomography, magnetic resonance spectroscopy and optical (fluorescent and bioluminescent) techniques. It was demonstrated that MMI can evaluate the distribution and function/activity of the triple suicide gene. The concomitant expression of these genes significantly enhances prodrug cytotoxicity and radiosensitivity in vitro and in vivo.

Subinhibitory concentrations of pinocembrin exert anti-Staphylococcus aureus activity by reducing α-toxin expression

AIMS

Natural products have been used as potentially important sources of novel antibacterials in combating pathogenic Staphylococcus aureus isolates, a major problem around the world. In this study, we aimed to investigate the antibacterial effects of pinocembrin (PNCB) against Staph. aureus pneumonia in a murine model and its influence on the production of Staph. aureus α-haemolysin (Hla).

METHODS AND RESULTS

The in vitro activities of PNCB on α-haemolysin production were determined using haemolysis, Western blot and real-time RT-PCR assays. The viability and cytotoxicity assays were performed to evaluate the influence of PNCB on α-toxin-mediated injury of human alveolar epithelial cells. Moreover, through histopathologic analysis, we further determined the in vivo effects of PNCB on Staph. aureus pneumonia in a mouse model. In vitro, PNCB at low concentrations exhibited inhibitory activity against α-haemolysin production and attenuated α-haemolysin-mediated cell injury. Furthermore, the in vivo findings demonstrated that PNCB protected mice from Staph. aureus pneumonia.

CONCLUSIONS

We have provided new evidence of the effects of PNCB, which suggest that PNCB attenuated α-haemolysin-mediated cell injury and protected mice from Staph. aureus pneumonia.

SIGNIFICANCE AND IMPACT OF THE STUDY

The findings indicate that PNCB may be used as a basis for anti-Staphylococcus agent.

NK cell-based autologous immune enhancement therapy (AIET) for cancer

Natural killer (NK) cells have been known to enhance the host immune responses against cancer. NK cell number and cytotoxicity in patients with cancer is often low. Therefore, we developed a large-scale ex vivo NK cell expansion method without feeder layers and introduced NK cell-based autologous immune enhancement therapy (AIET). In this paper, we discuss the epidemiological data that show the relationship between NK activity and cancer incidence, monitoring of NK cell number and activity, anti-cancer activities of NK cells in vitro and in vivo and the effects of the combination of expanded NK cells with monoclonal antibody drugs on cancers through antibody-dependent cellular cytotoxicity. Finally, we also present the clinical cases of NK cell-based AIET and the effect of AIET on advanced stage of pancreatic cancer and on various advanced cancers refractory to conventional therapies. NK cell-based AIET might be a useful strategy in the multidisciplinary approach to cancer.

Spray-dried plasma and fresh frozen plasma modulate permeability and inflammation in vitro in vascular endothelial cells

BACKGROUND

After major traumatic injury, patients often require multiple transfusions of fresh frozen plasma (FFP) to correct coagulopathy and to reduce bleeding. A spray-dried plasma (SDP) product has several logistical benefits over FFP use in trauma patients with coagulopathy. These benefits include ease of transport, stability at room temperature, and rapid reconstitution for infusion. Our past work suggests that FFP promotes endothelial stability by inhibiting endothelial permeability.

STUDY DESIGN AND METHODS

The main goal of this project is to determine if solvent-detergent-treated SDP is equivalent to FFP in inhibiting vascular endothelial cell (EC) permeability and inflammation in vitro. Furthermore, this study aimed to determine if solvent-detergent treatment and spray drying of plasma alters the protective effects of FFP on EC function. The five groups tested in our studies are the following: 1) fresh frozen-thawed plasma (FFP); 2) solvent-detergent-treated FFP; 3) solvent-detergent-treated SDP; 4) lactated Ringer's solution; and 5) Hextend.

RESULTS

This study demonstrates that in vitro SDP and FFP equivalently inhibit vascular EC permeability, EC adherens junction breakdown, and endothelial white blood cell binding, an effect that is independent of changes in Vascular Cell Adhesion Molecule 1, Intracellular Adhesion Molecule 1, or E-selectin expression on ECs. Solvent-detergent treatment of FFP does not alter the protective effects of FFP on endothelial cell function in vitro.

CONCLUSION

These data suggest the equivalence of FFP and SDP on modulation of endothelial function and inflammation in vitro.

[Protective effects of PEG modified recombinant cytoglobin on acute liver injury in mice]

To investigate the protective effect of polyethylene glycol (PEG) modified recombinant cytoglobin (PEG-rCygb) on acute liver damage in mice. The acute liver injury model of KM mice was induced by CCl4 and then treated with PEG-rCygb, The liver and blood samples were collected for biochemical and histopathological analysis. The results showed that PEG-rCygb reduced the liver mass index and decreased significantly the levels of alanine amiotransferase (AST) and aspartate transaminase (ALT) in mouse serum. In liver tissues, the content of malondialdehyde (MDA) was decreased, whereas the content of glutathione (GSH) was increased in PEG-rCygb treated group. PEG-rCygb also elevated the activities of total super oxidedismutase (T-SOD) and catalase (CAT) in liver tissues. HE staining of liver tissue slices revealed that PEG-rCygb relieved fatty degeneration of liver, decreased inflammatory factors and reduced liver cell injury. Further in vitro experiments indicated that the protective effects of PEG-rCygb on hepatic stellate cell (HSC) against H2O2 were enhanced compared with that of rCygb. All results indicated that the PEG-rCygb promoted oxygen free radical scavenging ability and prevented acute liver injury in KM mice induced by CCl4.