Telomerase inhibition strategies by siRNAs against either hTR or hTERT in oral squamous cell carcinoma

Human telomerase RNA (hTR) and human telomerase reverse transcriptase (hTERT) are considered effective molecular targets for current anticancer therapy. In this study, we investigated the therapeutic effects of targeting hTR and hTERT individually or in combination by recombinant adenovirus-delivered small interfering RNA (siRNA) in oral squamous cell carcinoma (OSCC) Tca8113. Further, we screened the optimal strategy for RNA interference. Our results show that these different recombinant adenoviruses specifically reduced the levels of hTR mRNA, hTERT mRNA, hTERT protein and telomerase activity in Tca8113 cells. Moreover, they successfully inhibited xenograft tumor growth in nude mice. The potency of their antitumor activities was ranked as follows: anti-hTR >anti-hTR+anti-hTERT >anti-hTERT. Therefore, we demonstrated that the siRNA-expressing recombinant adenoviruses were an effective anticancer tool for treatment of OSCC. Furthermore, the anticancer effect of solely targeting hTR was more direct and efficient, compared with the effect of targeting hTR and hTERT in combination, or hTERT exclusively. The mechanism of this anticancer effect in OSCC was not only related to the inhibition of cell proliferation and the induction of cell apoptosis, but might also involve the inhibition of tumor angiogenesis.

Determination of the width of the top quark

We extract the total width of the top quark, Γ(t), from the partial decay width Γ(t → Wb) measured using the t-channel cross section for single top-quark production and from the branching fraction B(t → Wb) measured in tt events using up to 2.3  fb(-1) of integrated luminosity collected by the D0 Collaboration at the Tevatron pp Collider. The result is Γ(t) = 1.99(-0.55)(+0.69)  GeV, which translates to a top-quark lifetime of τ(t) = (3.3(-0.9)(+1.3)) × 10(-25)   s. Assuming a high mass fourth generation b' quark and unitarity of the four-generation quark-mixing matrix, we set the first upper limit on |V(tb')| < 0.63 at 95% C.L.

Interpreting the stress response of early mammalian embryos and their stem cells

This review analyzes and interprets the normal, pathogenic, and pathophysiological roles of stress and stress enzymes in mammalian development. Emerging data suggest that stem cells from early embryos are induced by stress to perform stress-enzyme-mediated responses that use the strategies of compensatory, prioritized, and reversible differentiation. These strategies have been optimized during evolution and in turn have aspects of energy conservation during stress that optimize and maximize the efficacy of the stress response. It is likely that different types of stem cells have varying degrees of flexibility in mediating compensatory and prioritized differentiation. The significance of this analysis and interpretation is that it will serve as a foundation for yielding tools for diagnosing, understanding normal and pathophysiological mechanisms, and providing methods for managing stress enzymes to improve short- and long-term reproductive outcomes.

Search for ZH → l+ l- bb production in 4.2 fb(-1) of pp collisions at sqrt[s] =1 .96 TeV

We present a search for the standard model Higgs boson produced in association with a Z boson in 4.2 fb(-1) of pp collisions, collected with the D0 detector at the Fermilab Tevatron at sqrt[s] =1 .96 TeV. Selected events contain one reconstructed Z → e+ e- or Z → μ+ μ- candidate and at least two jets, including at least one b-tagged jet. In the absence of an excess over the background expected from other standard model processes, limits on the ZH cross section multiplied by the branching ratios are set. The limit at M(H) = 115  GeV is a factor of 5.9 larger than the standard model prediction.

Abstract P1-11-11: Correlation between ER/PgR/Her-2/Ki67 Expression and Response to Neoadjuvant Endocrine Therapy for HR Positive Post-Menopausal Breast Cancer

Background: Endocrine therapy was standard adjuvant treatment for hormone receptor positive breast cancer. However, there were factors other than receptor status could influence endocrine responsiveness. Neoadjuvant therapy was an excellent platform for predictive factors research, but the standard for evaluating the efficacy of neoadjuvant endocrine therapy was controversy. The aim of this study was to investigate the correlation among the results of different response evaluation system, and the relationships between ER/PgR/Her-2/Ki67 expression and the responses to neoadjuvant endocrine therapy for postmenopausal breast cancer.

Methods: Data of consecutive 133 core needle biopsy (CNB) confirmed hormone receptor strongly positive (more than 50% tumor cell stained ER or PgR) postmenopausal breast cancer treated with neoadjuvant endocrine therapy were analysis retrospectively. All pts. were planned to receive endocrine therapy alone as their adjuvant treatment and prescribed Anastrozole 1 mg per day for 16 weeks before surgery. Clinical response were evaluated by using documented ultrasound records,pathological response was evaluated by one senior pathologist with Miller & Payne classification. Cell cycle complete response was defined as post-treatment Ki67 ≥1%. The new slides of pre-treatment and surgical specimens were made for ER/PgR (ER\PR DakoCytomation)/Her-2 (Her-2 Dako HercepTest TM)/Ki67 (Ki67 Ventana) immunohistochemical staining through Benchmark XT Staining Instrument (Ventana Medical Systems. Inc. Arizona. USA) and classified by using image analysis system Ariol (Applied Imaging Inc., San-Jose, California, USA).

Results: Clinical response were CR:0.8% PR:33.1% SD:66.1%, pathological response were G5:3% G4+G3:47.4% G2+G1:49.6%, Ki67 change were &lt;1%: 22.8% decrease but &gt;1%:45.1% no decrease: 32.1%. The correlation and consistency among the response evaluated differently were poor [table 1]. The per-treatment ER/PR/Her-2/Ki67 showed low degree of correlation with responses [table 2]. Pre-treatment ER≥90% and PR≥90% and Her-2 coudln't predict better response.

The correlation and consistency among response evaluated in different system

Conclusion: The correlation and consistency among the results of response to neoadjuvant endocrine therapy evaluated by different system were poor. ER/PgR/Her-2/Ki67 showed low degree of correlation to responses. It's difficult to predict response to Arimidex neoadjuvant endocrine therapy by using ER/PgR/Her-2/Ki67 expression.

Abstract P1-01-27: Level III and Interpectoral Lymph Nodes Involvement in Breast Cancer with Positive Axillary Lymph Nodes after Neoadjuvant Chemotherapy

Background: In the era of sentinel node biopsy (SNB), mainly aimed at local control, the axillary dissection (AD) was performed for breast cancer with positive node. It was argued that only level I/II lymph nodes dissection might be inadequate because nodes involvement was found in level III and interpectoral region when axillary node was positive. It is necessary to assess the extent of AD after modern preoperative axillary staging. The aim of this study was to investigate the incidence and associated factors of node involvement in level III/interpectoral region. Methods: A consecutive series of 338 core needle biopsy confirmed T0-2 invasive breast cancer cases were included in this study. Axillary node metastases were proved by ultrasound guided needle biopsy (NB) if ultrasonographic abnormal node was detected prior to SNB or by SNB if no abnormal node was detected. Cases of negative NB but positive SNB with image abnormal node were excluded. Prior to AD included level III and interpectoral lymph nodes, 4 to 8 cycles of neoadjuvant chemotherapy with anthrocyclin and/or taxane regimen were completed for each case. The chi-square test was used to determine the relation between level III/interpectoral lymph nodes metastases and clinicopathological factors. Multivariate logistic regression was analyzed for covariate selection. Results: A median of 19 axillary nodes was harvested per case (range: 5-46, average: 19.2). The pathologic complete response rate of axillary nodes was 35.3% (70/198) in NB positive subgroup. Level III and interpectoral lymph nodes were harvested in 76.9% (260/338) of cases (range: 1-8, average: 1.9, median: 1) and 49.7% (168/338) of cases (range: 1-10, average: 1.6, median: 1), respectively. The incidence of positive level III and interpectoral lymph nodes were 8.9% (30/338) and 8.9% (30/338), respectively. Node involvement of level III/interpectoral region was found in 13.3% (45/338) of these cases. The incidence of node involvement in level III/interpectoral region of NB positive subgroup (14.6%, 29/198) was not significantly higher compared with SNB positive subgroup (11.4%, 16/140, P=0.391). Increasing tumor size was significantly correlated with increasing likelihood of node involvement in level III/interpectoral region (T0-1: 6.3% vs T2: 16.7%, P=0.008). In SNB positive T0-1 subgroup, there was no positive node found in level III/interpectoral region. Multivariate analysis showed that tumor size was the only independent factors predicting node involvement in level III/interpectoral region (OR=3.488, 95%CI:1.427-8.528, P=0.006).

Conclusions: The incidence of node involvement in level III/interpectoral region was 13.3% of nodes positive T0-2 breast cancer treated with neoadjuvant chemotherapy. Tumor size may be the predictor of node involvement in this region.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-01-27.

Diagnostic algorithm to differentiate lymphoma from inflammation in feline small intestinal biopsy samples

Differentiating between inflammatory bowel disease (IBD) and small intestinal lymphoma in cats is often difficult, especially when only endoscopic biopsy specimens are available for evaluation. However, a correct diagnosis is imperative for proper treatment and prognosis. A retrospective study was performed using surgical and endoscopic intestinal biopsy specimens from 63 cats with a history of chronic diarrhea or vomiting or weight loss. A diagnosis of lymphoma or inflammation was based on microscopic examination of hematoxylin and eosin (HE)-stained sections alone, HE-stained sections plus results of immunohistochemical labeling (IHC) for CD3e and CD79a, and HE staining, immunophenotyping, and polymerase chain reaction (PCR) results for B and/or T cell clonality. In addition, various histomorphologic parameters were evaluated for significant differences between lymphoma and IBD using Fisher's exact test. The sensitivity and specificity of each parameter in the diagnosis of lymphoma were also determined. Results of Bayesian statistical analysis demonstrated that combining histologic evaluation of small intestinal biopsy specimens with immunophenotyping and analysis of clonality of lymphoid infiltrates results in more accurate differentiation of neoplastic versus inflammatory lymphocytes. Important histologic features that differentiated intestinal lymphoma from IBD included lymphoid infiltration of the intestinal wall beyond the mucosa, epitheliotropism (especially intraepithelial nests and plaques), heterogeneity, and nuclear size of lymphocytes. Based on the results of this study, a stepwise diagnostic algorithm that first uses histologic assessment, followed by immunophenotyping and then PCR to determine clonality of the lymphocytes, was developed to more accurately differentiate between intestinal lymphoma and IBD.

Search for diphoton events with large missing transverse energy in 6.3 fb(-1) of pp collisions at √s=1.96 TeV

We report a search for diphoton events with large missing transverse energy produced in pp collisions at √s=1.96  TeV. The data were collected with the D0 detector at the Fermilab Tevatron Collider and correspond to 6.3  fb(-1) of integrated luminosity. The observed missing transverse energy distribution is well described by the standard model prediction, and 95% C.L. limits are derived on two realizations of theories beyond the standard model. In a gauge-mediated supersymmetry breaking scenario, the breaking scale Λ is excluded for Λ<124  TeV. In a universal extra dimension model including gravitational decays, the compactification radius R(c) is excluded for R(c)(-1)<477  GeV.

Search for new fermions ("quirks") at the Fermilab Tevatron collider

We report results of a search for particles with anomalously high ionization in events with a high transverse energy jet and large missing transverse energy in 2.4 fb⁻¹ of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron pp collider. Production of such particles (quirks) is expected in scenarios with extra QCD-like SU(N) sectors, and this study is the first dedicated search for such signatures. We find no evidence of a signal and set a lower mass limit of 107, 119, and 133 GeV for the mass of a charged quirk with strong dynamics scale Λ in the range from 10 keV to 1 MeV and N=2, 3, and 5, respectively.

Search for events with leptonic jets and missing transverse energy in pp collisions at √s=1.96 TeV

We present the first search for pair production of isolated jets of charged leptons in association with a large imbalance in transverse energy in pp collisions using 5.8 fb⁻¹ of integrated luminosity collected by the D0 detector at the Fermilab Tevatron Collider. No excess is observed above the standard model background, and the result is used to set upper limits on the production cross section of pairs of supersymmetric chargino and neutralino particles as a function of "dark-photon" mass, where the dark photon is produced in the decay of the lightest supersymmetric particle.

Single crystal study of competing rhombohedral and monoclinic order in lead zirconate titanate

Neutron diffraction data obtained on single crystals of PbZr(1-x)Ti(x)O3 with x=0.325 and x=0.460, which lie on the pseudorhombohedral side of the morphotropic phase boundary, suggest a coexistence of rhombohedral (R3m/R3c) and monoclinic (Cm) domains and that monoclinic order is enhanced by Ti substitution. A monoclinic phase with a doubled unit cell (Cc) is ruled out as the ground state.

Search for sneutrino production in eμ final states in 5.3 fb-1 of pp collisions at square root s =1.96 TeV

We report the results of a search for R parity violating (RPV) interactions leading to the production of supersymmetric sneutrinos decaying into eμ final states using 5.3 fb-1 of integrated luminosity collected by the D0 experiment at the Fermilab Tevatron Collider. Having observed no evidence for production of eμ resonances, we set direct bounds on the RPV couplings λ311' and λ312 as a function of sneutrino mass.

Cellular stress causes reversible, PRKAA1/2-, and proteasome-dependent ID2 protein loss in trophoblast stem cells

Stress reduces fertility, but the mechanisms mediating this are not understood. For a successful pregnancy, placental trophoblast stem cells (TSCs) in the implanting embryo proliferate and then a subpopulation differentiates to produce hormones. Normally, differentiation occurs when inhibitor of differentiation 2 (ID2) protein is lost in human and mouse placental stem cells. We hypothesize that stress enzyme-dependent differentiation occurs in association with insufficient TSC accumulation. We studied a well-defined model where TSC differentiation requires ID2 loss. The loss of ID2 derepresses the promoter of chorionic somatomammotropin hormone 1 (CSH1), the first hormone after implantation. Csh1 mRNA is known to be induced in stressed TSCs. In this study, we demonstrate that AMP-activated protein kinase (PRKAA1/2, aka AMPK) mediates the stress-induced proteasome-dependent loss of ID2 at high stress levels. At very low stress levels, PRKAA1/2 mediates metabolic adaptation exemplified by the inactivation of acetyl coA carboxylase by phosphorylation without ID2 loss. At the highest stress levels, irreversible TSC differentiation as defined by ID2 loss and slower cell accumulation occurs. However, lower stress levels lead to reversible differentiation accompanied by metabolic adaptation. These data support the hypothesis that PRKAA1/2 mediates preparation for differentiation that is induced by stress at levels where a significant decrease in cell accumulation occurs. This supports the interpretation that enzyme-mediated increases in differentiation may compensate when insufficient numbers of stem cells accumulate.

Specific disruption of astrocytic Ca2+ signaling pathway in vivo by adeno-associated viral transduction

Astrocytes are the predominant glial-cell type in the CNS and they are known to play an active role in modulating neuronal function. Since many of the same molecules including G-protein coupled receptors (GPCRs) are expressed in both neurons and astrocytes, in vivo pharmacological manipulations to target astrocytes lack specificity. In this study, we investigated the effect of Pleckstrin Homology (PH) domain of Phospholipase C (PLC)-like protein p130 (p130PH) on Ca(2+) signaling in astrocytes in vivo. We used the serotype 2/5 recombinant adeno-associated virus (rAAV2/5) vectors to introduce p130PH fused with a tagged protein monomer red fluorescent protein at the N-terminal (i.e., transgene mRFP-p130PH). In order to selectively disrupt the Ca(2+) signaling pathway in astrocytes, the transgene was driven by a novel astrocyte-specific promoter gfaABC(1)D. Our results show that mRFP-p130PH is exclusively expressed in astrocytes with a high efficiency and a stable expression level. In vivo imaging using two-photon microscopy demonstrated reduced Ca(2+) signal in transduced astrocytes in response to ATP stimulation. As Ca(2+) signaling is a characteristic form of cellular excitability in astrocytes that can mediate chemical transmitter release and contribute to neuronal excitotoxicity, the current study provides an in vivo approach to better understand Ca(2+)-dependent gliotransmission and its involvement in glia-related diseases.

Evidence for an anomalous like-sign dimuon charge asymmetry

We measure the charge asymmetry A ≡ (N++ - N--)/(N++ + N--) of like-sign dimuon events in 6.1 fb-1 of pp collisions recorded with the D0 detector at a center-of-mass energy square root(s) = 1.96   TeV at the Fermilab Tevatron collider. From A we extract the like-sign dimuon charge asymmetry in semileptonic b-hadron decays: A(sl)(b) = -0.009 57 ± 0.002 51(stat) ± 0.001 46(sys). It differs by 3.2 standard deviations from the standard model prediction A(sl)(b)(SM) = (-2.3(-0.6)(+0.5)) × 10(-4), and provides first evidence of anomalous CP violation in the mixing of neutral B mesons.

Determination of Imazaquin and its metabolite by liquid chromatography-quadrupole-time of flight tandem mass

A method consisting of solvent extraction followed by liquid chromatography-quadrupole-time of flight- tandem mass spectrometry analysis was developed for the identification of Imazaquin and its metabolite. The relationships between detector response and sample concentrations showed a high degree of linearity (r > 0.998) over the range 0.03-10 microg/g. The recoveries obtained were in the acceptable range of 86%-104% between spiked. The relative standard deviation of this method was 6.4%-17.1%. A 35-day study of Imazaquin degradation was taken in agricultural soil from Binzhou, China. The degradation followed first order kinetics (C = 0.7672e(-0.0774t)), with half-life of less than 8.5 days. Investigation of the by-products from liquid chromatography-quadrupole-time of flight- tandem mass spectrometry has shown that there were four important metabolites 4-methylene-2-(quinolin-2-yl)-1H-imidazol-5(4H)-one, quinoline-3-carbaldehyde, 1-amino-2,3-dimethyl-1-oxobutan-2-ylium and 1H-[1,2]oxazino[4,5-b]quinolin-1-one in the degradation process. The accurate mass measurements error was 5 ppm in this study. The method was successfully applied to the analysis of imazaquin and its metabolite residues in soil.

Search for Randall-Sundrum gravitons in the dielectron and diphoton final states with 5.4 fb(-1) of data from pp collisions at square root(s) = 1.96 TeV

Using 5.4  fb(-1) of integrated luminosity from pp collisions at square root(s)=1.96  TeV collected by the D0 detector at the Fermilab Tevatron Collider, we search for decays of the lightest Kaluza-Klein mode of the graviton in the Randall-Sundrum model to ee and γγ. We set 95% C.L. lower limits on the mass of the lightest graviton between 560 and 1050 GeV for values of the coupling k/M(Pl) between 0.01 and 0.1.

Pregnane X receptor suppresses proliferation and tumourigenicity of colon cancer cells

BACKGROUND

Pregnane X receptor (PXR) is a nuclear receptor that regulates the metabolism and disposition of various xenobiotics and endobioitics. We investigated a novel PXR function in regulating colon tumourigenesis in this study.

METHODS

Histochemistry, transfection, cell proliferation assay, anchorage-alpha-dependent assay, xenograft, immunohistochemistry, immunofluorescence flow cytometry.

RESULTS

Using histochemistry analysis, we found that PXR expressions were lost or greatly diminished in many colon tumours. Ectopic expression of human PXR through stable transfection of PXR into colon cancer cell line HT29 significantly inhibited cell proliferation as determined by cell proliferation assay and anchorage-independent assay. Pregnane X receptor suppressed significantly HT29 xenograft tumour growth in nude mice compared with control (310+/-6.2 vs 120+/-6 mg, P<0.01). Immunohistochemistry and immunofluorescence analysis of Ki-67 on excised xenograft tumour tissues showed that PXR inhibited cancer cell proliferation. Furthermore, expressions of PXR and Ki-67 were mutually exclusive. The flow cytometry analysis indicated that PXR caused G(0)/G(1) cell-cycle arrest. p21(WAF1/CIP1) expression was markedly elevated whereas E2F1 expression was inhibited by PXR.

CONCLUSION

PXR inhibits the proliferation and tumourigenicity of colon cancer cells by controlling cell cycle at G(0)/G(1) cell phase by regulating p21(WAF1/CIP1) and E2F/Rb pathways.

Entry of hepatitis B virus: mechanism and new therapeutic target

Entry of hepatitis B virus (HBV) into human hepatocytes constitutes the initial step in viral infection. The study of HBV entry had long been hampered by the lack of efficient cell culture systems and small animal models. The situation was greatly improved in the last decade with the development of HBV-infectible HepaRG cell line and primary Tupaia hepatocyte culture. Armed with these new tools, marked progresses have been achieved in the elucidation of the mechanism of HBV entry. Plenty of evidences indicate that the viral large surface protein (LHBs) is essential for HBV entry. Several regions in the PreS1 domain of LHBs have been verified to contribute directly to the viral attachment. In addition, a myristate moiety linked to the N-terminal glycine of PreS1 appears critical for HBV infectivity. Recently, the cysteine-rich antigenic loop of the S domain was identified as another crucial determinant for HBV infectivity. On the other hand, several cellular proteins were implicated in HBV attachment to hepatic cells, though definitive proofs are required in support to their functional involvement in HBV infection. Aiming to blocking viral entry, a couple of approaches based on acylated PreS1-derived peptides and short PreS1-binding peptides are currently under investigation, which have the potential to become novel antiviral therapeutics.