NANOG promotes cancer stem cell characteristics and prostate cancer resistance to androgen deprivation

Cancer cell molecular mimicry of stem cells (SC) imbues neoplastic cells with enhanced proliferative and renewal capacities. In support, numerous mediators of SC self-renewal have been evinced to exhibit oncogenic potential. We have recently reported that shRNA-mediated knockdown of the embryonic stem cell (ESC) self-renewal gene NANOG significantly reduced the clonogenic and tumorigenic capabilities of various cancer cells. In this study, we sought to test the potential pro-tumorigenic functions of NANOG, particularly, in prostate cancer (PCa). Using quantitative RT-PCR, we first confirmed that PCa cells expressed NANOG mRNA primarily from the NANOGP8 locus on chromosome 15q14. We then constructed a lentiviral promoter reporter in which the -3.8 kb NANOGP8 genomic fragment was used to drive the expression of green fluorescence protein (GFP). We observed that NANOGP8-GFP⁺ PCa cells exhibited cancer stem cell (CSC) characteristics such as enhanced clonal growth and tumor regenerative capacity. To further investigate the functions and mechanisms of NANOG in tumorigenesis, we established tetracycline-inducible NANOG overexpressing cancer cell lines, including both prostate (Du145 and LNCaP) and breast (MCF-7) cancer cells. NANOG induction promoted drug-resistance in MCF-7 cells, tumor regeneration in Du145 cells, and, most importantly, castration-resistant tumor development in LNCaP cells. These pro-tumorigenic effects of NANOG were associated with key molecular changes, including an upregulation of molecules such as CXCR4, IGFBP5, CD133 and ALDH1. The present gain-of-function studies, coupled with our recent loss-of-function work, establish the integral role for NANOG in neoplastic processes and shed light on its mechanisms of action.

ATM-mediated phosphorylation activates the tumor-suppressive function of B56γ-PP2A

Protein phosphatase 2A (PP2A) is a family of heterotrimeric protein phosphatases that has a multitude of functions inside the cell, acting through various substrate targets in cell-signaling pathways. Recent evidence suggests that a subset of PP2A holoenzymes function as tumor suppressors and one particular family of B subunits, B56, are implicated in this function. However, the regulatory mechanisms that govern activation of B56-PP2A tumor-suppressive function have not been elucidated. In the present study, we demonstrate that ataxia-telangiectasia mutated (ATM) directly phosphorylates and specifically regulates B56γ3, B56γ2 and B56δ, after DNA damage. We further show that phosphorylation of B56γ3 at Ser510 leads to an increase in B56γ3-PP2A complexes, and direction of PP2A phosphatase activity toward the substrate p53, activating its tumor-suppressive functions. In addition, we found that under cell growth conditions B56γ3 is kept at low levels through the actions of the E3 ubiquitin ligase MDM2, and, importantly, phosphorylation of B56γ3 by ATM leads to upregulation of the protein by blocking MDM2-mediated B56γ3 ubiquitination. Finally, we show that Ser510 phosphorylation significantly enhances the ability of B56γ3 to inhibit cell proliferation and anchorage-independent growth. These results provide mechanistic insight into the regulation of PP2A tumor-suppressive function, and suggest a model for parallel regulation of p53 and B56γ3.

Pharmacokinetics and pharmacodynamics of dapagliflozin, a novel selective inhibitor of sodium-glucose co-transporter type 2, in Japanese subjects without and with type 2 diabetes mellitus

AIMS

Dapagliflozin, a selective, orally active inhibitor of the renal sodium-glucose co-transporter type 2 (SGLT2) is in development for the treatment of type 2 diabetes mellitus (T2DM). Here, the pharmacokinetics (PK) and pharmacodynamics (PD) of dapagliflozin were evaluated in healthy Japanese subjects and in Japanese subjects with T2DM.

METHODS

Two studies were conducted: a single-ascending dose (SAD) study (2.5-50 mg) in 32 healthy subjects and a multiple-ascending dose (MAD) study (2.5-20 mg QD for 14 days) in 36 subjects with T2DM. Safety and tolerability were assessed in both studies. Single and multiple dose PK of dapagliflozin and its inactive major metabolite, dapagliflozin 3-O-glucuronide, and PD (urinary glucose parameters) were characterized. Plasma glucose parameters were assessed over 14 days in the MAD study.

RESULTS

No serious adverse events or discontinuations due to adverse events occurred in either study. In healthy and T2DM subjects, dapagliflozin was rapidly absorbed with a time to maximum plasma concentration of 0.5-1.3 h. Systemic exposure of dapagliflozin and dapagliflozin 3-O-glucuronide, measured by maximum plasma concentration and area under the plasma concentration-time curve, increased proportional to dose. On a molar basis, systemic exposure to dapagliflozin 3-O-glucuronide was similar to parent dapagliflozin. There was a dose-related increase in the amount of glucose excreted in the urine (SAD and MAD), which was associated with dose-related decreases in plasma glucose parameters in subjects with T2DM (MAD).

CONCLUSIONS

Dapagliflozin was well tolerated and showed predictable dose-proportional PK and PD parameters in both healthy and T2DM Japanese subjects.

Performance of sequential organ failure assessment, logistic organ dysfunction and multiple organ dysfunction score in severe sepsis within Chinese intensive care units

This study assessed the performance of Sequential Organ Failure Assessment, Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score in outcome prediction in severe sepsis. A total of 528 consecutive patients with a diagnosis of severe sepsis were enrolled from two surgical intensive care units of university hospitals in China. Clinical and laboratory data of patients were collected and admission and maximum values of each scoring system were calculated. Areas under the receiver operating characteristic curve, which were used to assess discrimination, were 0.80, 0.83 and 0.74 for admission Sequential Organ Failure Assessment, Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score respectively, and 0.91, 0.93 and 0.86 for corresponding maximum values respectively. Calibration assessed by the Hosmer-Lemeshow statistic was better with admission (chi2 = 18.2) and maximum Logistic Organ Dysfunction Score (chi2 = 19.6) than with admission (chi2 = 98.1) and maximum Multiple Organ Dysfunction Score (chi2 = 30.9). Brier Scores, indicating the overall performance of the scores, were 0.18, 0.17 and 0.22 for admission Sequential Organ Failure Assessment, Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score respectively, and 0.12, 0.10 and 0.15 for their maximum counterparts respectively. This study found good performance of both admission Sequential Organ Failure Assessment and Logistic Organ Dysfunction Score in severe sepsis, and a slightly weaker performance of admission Multiple Organ Dysfunction Score. Since poor calibration was observed in Logistic Organ Dysfunction Score and Multiple Organ Dysfunction Score, we suggest further study of customisation of these scores in critical illness with severe sepsis.

Altered fusion dynamics underlie unique morphological changes in mitochondria during hypoxia-reoxygenation stress

Functional states of mitochondria are often reflected in characteristic mitochondrial morphology. One of the most fundamental stress conditions, hypoxia-reoxygenation has been known to cause impaired mitochondrial function accompanied by structural abnormalities, but the underlying mechanisms need further investigation. Here, we monitored bioenergetics and mitochondrial fusion-fission in real time to determine how changes in mitochondrial dynamics contribute to structural abnormalities during hypoxia-reoxygenation. Hypoxia-reoxygenation resulted in the appearance of shorter mitochondria and a decrease in fusion activity. This fusion inhibition was a result of impaired ATP synthesis rather than Opa1 cleavage. A striking feature that appeared during hypoxia in glucose-free and during reoxygenation in glucose-containing medium was the formation of donut-shaped (toroidal) mitochondria. Donut formation was triggered by opening of the permeability transition pore or K(+) channels, which in turn caused mitochondrial swelling and partial detachment from the cytoskeleton. This then favored anomalous fusion events (autofusion and fusion at several sites among 2-3 mitochondria) to produce the characteristic donuts. Donuts effectively tolerate matrix volume increases and give rise to offspring that can regain ΔΨ(m). Thus, the metabolic stress during hypoxia-reoxygenation alters mitochondrial morphology by inducing distinct patterns of mitochondrial dynamics, which includes processes that could aid mitochondrial adaptation and functional recovery.

Note: Diagnosing femtosecond laser-solid interactions with monochromatic Kα imager and x-ray pinhole camera

An x-ray pinhole camera and a monochromatic K(α) imager are used to measure the interactions of intense femtosecond laser pulses with Cu foil targets. The two diagnostics give different features in the spot size and the laser energy scaling, which are resulted from different physical processes. Under our experimental conditions, the K(α) emission is mainly excited by the fast electrons transporting inside the cold bulk target. In contrast, the x-ray pinhole signals are dominated by the broadband thermal x-ray emission from the hot plasma at the front target surface.

Study on the executive function and learning ability in first-episode schizophrenia patients

Introduction

Cognitive dysfunction was thought to be one of the core features of schizophrenia. And the executive function of the patients was paid more attention by more and more researchers and clinicians.

Objectives

To investigate the executive function and the learning ability of the patients with first-episode schizophrenia, and their relationships with psychiatric symptoms.

Methods

Fifty cases of first-episode schizophrenia patients and fifty age- and gender-matched healthy controls were tested by a computerized version of Tower of London (TOL) test. The scores of the Positive and Negative Syndrome Scale(PANSS) in the group of schizophrenia patients were over 60.

Results

The numbers of the correct answer [x1 :(14.62 ± 4.12), x2: (14.80 ± 4.70)] during the first session and the second session of the TOL test of the patients group were significantly lower than that of the control group [x1: (17.48 ± 3.79), x2:(18.68 ± 3.19)], and the reaction times [t1: (9.27 ± 4.37) seconds, t2: (9.51 ± 5.58) seconds] of the two sessions of TOL were longer than the control group [t1: (7.28 ± 2.04) seconds, t2: (6.67 ± 1.51) seconds], P < 0.01. For the control group, x2 was significantly greater than x1, and t2 shorter than t1 (P < 0.01), while for the patients group, there was no difference between the performances of the first session and the second session. The scores of TOL in the schizophrenia patients were correlated with the negative symptom score of PANSS (P < 0.05) and were not correlated with the scores of other subscales of PANSS (P > 0.05).

Conclusions

The executive function and the learning ability of schizophrenia are impaired and the cognitive dysfunction is correlated with negative symptoms.

TNF-α acutely upregulates amylin expression in murine pancreatic beta cells

AIMS/HYPOTHESIS

Amylin, a secretory protein mainly produced by pancreatic beta cells, is elevated in the circulation of patients with diseases related to acute and chronic inflammation, including acute pancreatitis, pancreas graft rejection, obesity and insulin resistance. TNF-α is involved in these disorders. We investigated the effect of TNF-α on amylin levels and the underlying mechanisms, using murine pancreatic beta cell line MIN6 and pancreatic islets.

METHODS

Amylin, proinsulin and prohormone convertase 1/3, 2 (Pc1/3, Pc2 [also known as Pcsk1/3 and Pcsk2, respectively]) mRNA levels, and amylin promoter and nuclear factor κB (NF-κB) activation were examined by real-time PCR and luciferase reporter assay, respectively. Amylin protein level and mitogen-activated protein kinase phosphorylation were detected by western blot. Activator protein 1 (AP1) activation was examined by electrophoretic mobility shift assay (EMSA).

RESULTS

TNF-α acutely induced amylin expression at the transcriptional level and increased proamylin and the intermediate form of amylin in MIN6 cells and islets. However, it had no effect on proinsulin, Pc1/3 and Pc2 expression. Studies with (1) MIN6 cells treated with inhibitors of MEK1/2, c-Jun-N-terminal kinase (JNK) or protein kinase Cζ (PKC(ζ)), (2) MIN6 cells expressing a c-Jun-dominant negative construct and (3) islets from Fos knockout mice demonstrated that TNF-α induced amylin expression through the PKC(ζ)-extracellular signal-regulated kinase (ERK)/JNK pathways. EMSA showed that (PKC(ζ)), JNK and ERK1/2 were involved in TNF-α-induced AP1 activation, suggesting that TNF-α induces murine amylin expression through the (PKC(ζ)) - ERK1/2 - AP and PKC(ζ) - JNK - AP1 pathways. Further studies showed that TNF-α also induced murine amylin expression through the phosphatidylinositol 3 kinase-NF-κB signalling pathway and enhanced human amylin promoter activation through NF-κB and AP1.

CONCLUSIONS/INTERPRETATION

TNF-α acutely induces amylin gene expression in beta cells through multiple signalling pathways, possibly contributing to amylin elevation in acute inflammation-related pancreatic disorders.

Targeted combinatorial therapy of androgen receptor in androgen-independent prostate cancer cells

29

Background: Gain of function of androgen receptor (AR) and PI3K/Akt/mTOR pathway due to loss of PTEN function are interrelated determinants of AIPC progression and resistance to antiandrogens. We determined that histone deacetylase inhibitors (HDACi), known to regulate AR expression and transcriptional activity, restore sensitivity to bicalutamide (Bic) of AIPC cells and the combination is synergistic. We postulate that adding a dual inhibitor of PI3K/mTOR would potentiate growth inhibition and apoptotic response.

Methods: Androgen-independent, PTEN null AI-LNCaP (AI-cells) and wt PTEN RV1-cell lines were treated for 72h with the HDACi Panobinostat (PAN), the dual PI3K/mTOR inhibitor BEZ235 (E) and Bic as single agents or in doublet or triplet combinations. Growth was measured by MTT assay, Akt/mTOR pathway target proteins p-Akt, p-4EBP1 and p-S6K by western blot. Activation of ligand-independent AR downstream targets: CDC20, IDI1, CDK1, UBE2C, PRDM4 by qRT-PCR. Apoptosis by oligonucleosome quantification by ELISA was compared to docetaxel.

Results: In both cell lines, the IC50s were markedly reduced in response to the doublet combinations and further decreased by the triplet. The isobolograms showed synergy. The apoptosis response increased by two fold in AI and RV1 cells in response to the doublet PAN+E and by four fold with the addition of Bic in AI cells. Only E decreased the protein levels of p473-akt, p-4EBP1, p-S6K markedly while only PAN decreased AR and these levels were not affected by the combinations. However, the triplet but not the doublets decreased by 2-fold the expression of AR targets in AI-cells but not in RV1 cells.

Conclusions: The combination of PAN+E is highly effective in AIPC cells regardless of PTEN status but the addition of Bic is essential to maximize the effect in PTEN null AI-cells, suggesting they are more dependent on aberrant activation of AR.

[Table: see text]

No significant financial relationships to disclose.

Molecular analysis of an additional case of hybrid sterility in rice (Oryza sativa L.)

Hybrid sterility hinders the exploitation of the heterosis displayed by japonica × indica rice hybrids. The variation in pollen semi-sterility observed among hybrids between the japonica recipient cultivar and each of two sets of chromosome segment substitution lines involving introgression from an indica cultivar was due to a factor on chromosome 5 known to harbor the gene S24. S24 was fine mapped to a 42 kb segment by analyzing a large F(2) population bred from the cross S24-NIL × Asominori, while the semi-sterility shown by the F(1) hybrid was ascribable to mitotic failure at the early bicellular pollen stage. Interestingly, two other pollen sterility genes (f5-Du and Sb) map to the same region (Li et al. in Chin Sci Bull 51:675-680, 2006; Wang et al. in Theor Appl Genet 112:382-387, 2006), allowing a search for candidate genes in the 6.4 kb overlap between the three genes. By sequencing the overlapped fragment in wild rice, indica cultivars and japonica cultivars, a protein ankyrin-3 encoded by the ORF2 was identified as the molecular base for S24. A cultivar Dular was found to have a hybrid-sterility-neutral allele, S24-n, in which an insertion of 30 bp was confirmed. Thus, it was possible to add one more case of molecular bases for the hybrid sterility. No gamete abortion is caused on heterozygous maternal genotype with an impaired sequence from the hybrid-sterility-neutral genotype. This result will be useful in understanding of wide compatibility in rice breeding.

Different anesthesia methods for laparoscopic cholecystectomy

OBJECTIVES

The aim of the study was to compare the possibility of performing laparoscopic cholecystectomy using two different anesthesia procedures (spinal anesthesia versus general anesthesia).

METHODS

The study included 68 patients with symptoms of cholelithiasis examined in the 309th Hospital of PLA from 2006 to 2009. Patients were randomly selected to undergo laparoscopic cholecystectomy with low tension pneumoperitoneum with CO(2) under general anesthesia (n=33) or spinal anesthesia (n=35). The study used propofol, fentanyl, rocuronium, sevoflurane and tracheal intubation for general anesthesia and hyperbaric 15 mg bupivacaine and 20 µg fentanyl were used to achieve a sensorial level of T(3) for spinal anesthesia. Intraoperative parameters, postoperative pain, complications, recovery, patient satisfaction and cost were compared between both groups.

RESULTS

All surgical procedures were completed with the chosen method with the exception of one case, in which spinal anesthesia was converted to general anesthesia. Shoulder pain was significantly less frequent in the spinal anesthesia group (6%) compared with the general anesthesia group (24%). The level of pain at 2, 4, and 6 h after the procedure under spinal anesthesia was significantly lower than that under general anesthesia. At 12 h both groups had the same evaluation in the visual analogue scale. In the spinal anesthesia group all patients recovered 6 h after surgery, while patients in the general anesthesia group spent more time in recovery. All patients were discharged from hospital after 24 h. In the postoperative evaluation all patients were satisfied with the spinal anesthesia and would recommend this procedure, while only 78.9% of patients were very satisfied in the general anesthesia group. The cost of spinal anesthesia was significantly lower than that of general anesthesia.

CONCLUSIONS

Laparoscopic cholecystectomy with low pressure pneumoperitoneum with CO(2) can be safely performed under spinal anesthesia. Spinal anesthesia was associated with an extremely low level of postoperative pain, better recovery and lower cost than general anesthesia.

Metallization of GaN Thin Films Prepared by Ion Beam Assisted Molecular Beam Epitaxy

Gallium nitride has generated much interest due to its ability to emit light in the blue to UV range [1]. We have investigated the ohmic contact properties of various metals evaporated onto highly auto-doped n-type GaN thin films which were grown on basal sapphire substrates by ion-assisted molecular beam epitaxy (IAMBE). Electrical measurements of transmission line structures with the metals In, InSn and AuGeNi revealed a wide range of contact resistivity (10∼2 to 10-6 Ω-cm2) which changed with annealing.

Structural Defects in Heteroepitaxial and Homoepitaxial GaN

The microstructure and characteristic defects of heteroepitaxial GaN films grown on sapphire using molecular beam epitaxy (MBE) and metal-organic-chemical-vapor-deposition (MOCVD) methods and of homoepitaxial GaN grown on bulk substrates are described based on transmission electron microscopy (TEM), x-ray diffraction, and cathodoluminescence (CL) studies. The difference in arrangement of dislocations along grain boundaries and die influence of buffer layers on the quality of epitaxial films is described. The structural quality of GaN epilayers is compared to diat of bulk GaN crystals grown from dilute solution of atomic nitrogen in liquid gallium. The full width at half maximum (FWHM) of the x-ray rocking curves for these crystals was in the range of 20–30 arc sec, whereas for the heteroepitaxially grown GaN the FWHM was in the range of 5–20 arc min. Homoepitaxial MBE grown films had FWHMs of about 40 arc sec. The best film quality was obtained for homoepitaxial films grown using MOCVD; these samples were almost free from extended defects. For the bulk GaN crystals a substantial difference in crystal perfection was observed for the opposite sides of the plates shaped normal to the c direction. On one side the surface was almost atomically flat, and the underlying material was free of any extended structural defects, while the other side was rough, with a high density of planar defects. This difference was related to the polarity of the crystal. A large difference in crystal stoichiometry was also observed within different sublayers of the crystals. Based on convergent beam electron diffraction and cathodoluminescence, it is proposed that GaN antisite defects are related to the yellow luminescence observed in these crystals.

Confirmation of the X(1835) and observation of the resonances X(2120) and X(2370) in J/ψ→γπ+π-η'

With a sample of (225.2±2.8)×10(6) J/ψ events registered in the BESIII detector, J/ψ→γπ(+)π(-)η(') is studied using two η(') decay modes: η(')→π(+)π(-)η and η(')→γρ(0). The X(1835), which was previously observed by BESII, is confirmed with a statistical significance that is larger than 20σ. In addition, in the π(+)π(-)η(') invariant-mass spectrum, the X(2120) and the X(2370), are observed with statistical significances larger than 7.2σ and 6.4σ, respectively. For the X(1835), the angular distribution of the radiative photon is consistent with expectations for a pseudoscalar.

Laser Induced Avalanche Ionization and Electron-Lattice Heating of Silicon with Intense Near IR Femtosecond Pulses

A two temperature finite difference model has been developed and is used to describe the response of materials under ultrafast femtosecond laser pulses in the energy regime where melting and vaporization can occur. In applying this model to silicon it is observed that, for 800 nm light, laser pulse intensities that are just sufficient to achieve threshold for vaporization are also at the level of optical electric field strength where electron avalanche breakdown at the surface of the material can occur. For sub-picosecond pulses the physical response of the material is associated with a strongly temperature dependent coupling coefficient connecting electron and phonon thermal distributions. The results of these analyses demonstrate that a very thin near solid density plasma, caused by avalanche ionization, is responsible for the surface heating and subsequent thermodynamic response of the material. This interpretation is consistent throughout the pulse duration range from 80 femtoseconds to 0.2 nanoseconds. The proposed mechanism for absorption, at the near infra-red wavelength being used here, is very different from the types of mechanisms usually considered for nanosecond laser heating of semiconductors. Surface damage threshold is determined by atomic force microscopy and the threshold for plasma optical emission by photomultiplier detection . Melt deths are probed with SIMS impurity diffusion profiles and high resolution cross sectional TEM.

Transformation of wheat with the HMW-GS 1Bx14 gene without markers

High molecular weight (HMW) glutenin polypeptides are critical contributors to the visco/elastic properties responsible for the processing characteristics and utilizations of wheat flour. In order to improve bread making quality of flour and produce transgenic plants free of selectable markers, a linear DNA construct consisting of a minimal expression cassette with the HMW-GS 1Bx14 gene was transformed into wheat cultivar Mianyang 19 by microprojectile bombardment. The transformants were selected by PCR instead of herbicidal markers. Seven transgenic plants were identified from a total of 1219 transformants, yielding a transformation frequency of 0.28%. An SDS-PAGE analysis confirmed that the 1Bx14 gene was expressed in three T1 seeds of the transgenic plants. Our results demonstrated that it is feasible to obtain marker-free transformants using the linear-expression-cassette-transformation approach coupled with PCR selection.