Neuronostatin is co-expressed with somatostatin and mobilizes calcium in cultured rat hypothalamic neurons

Neuronostatin (NST) is a newly identified peptide of 13-amino acids encoded by the somatostatin (SST) gene. Using a rabbit polyclonal antiserum against the human NST, neuronostatin-immunoreactive (irNST) cells comparable in number and intensity to somatostatin immunoreactive (irSST) cells were detected in the hypothalamic periventricular nucleus. Fewer and/or less intensely labeled irNST cells were noted in other regions such as the hippocampus, cortex, amygdala, and cerebellum. Double-labeling hypothalamic sections with NST- and SST-antiserum revealed an extensive overlapping of irNST and irSST cells in the periventricular nucleus. Pre-absorption of the NST-antiserum with NST (1 microg/ml) but not with SST (1 microg/ml) abrogated irNST and vice versa. The activity of NST on dissociated and cultured hypothalamic neurons was assessed by the Ca(2+) imaging method. NST (10, 100, 1000 nM) concentration-dependently elevated intracellular Ca(2+) concentrations [Ca(2+)](i) in a population of hypothalamic neurons with two distinct profiles: (1) a fast and transitory increase in [Ca(2+)](i), and (2) an oscillatory response. Whereas, SST (100 nM) reduced the basal [Ca(2+)](i) in 21 of 61 hypothalamic neurons examined; an increase was not observed in any of the cells. Optical imaging with a slow-responding voltage sensitive dye DiBAC(4)(3) showed that NST (100 nM) depolarized or hyperpolarized; whereas, SST (100 nM) hyperpolarized a population of hypothalamic neurons. The result shows that NST and SST, though derived from the same precursor protein, exert different calcium mobilizing effects on cultured rat hypothalamic neurons, resulting in diverse cellular activities.

Loss of HBsAg antigen during treatment with entecavir or lamivudine in nucleoside-naïve HBeAg-positive patients with chronic hepatitis B

This retrospective analysis was conducted to describe the characteristics of nucleoside-naïve hepatitis B e antigen (HBeAg)-positive patients with chronic hepatitis B, who achieved hepatitis B surface antigen (HBsAg) loss during entecavir or lamivudine therapy. HBeAg-positive adults with chronic hepatitis B, elevated serum alanine aminotransferase, and compensated liver disease were randomized to double-blind treatment for up to 96 weeks with entecavir 0.5 mg/day or lamivudine 100 mg/day. HBsAg and hepatitis B virus (HBV) DNA were measured at regular intervals during and off-treatment follow-up. Through a maximum duration of 96 weeks on-treatment and 24 weeks off-treatment, HBsAg loss was confirmed in 18/354 (5.1%) patients treated with entecavir and 10/355 (2.8%) patients treated with lamivudine. Among the 28 patients with confirmed HBsAg loss, 27 (96%) achieved HBV DNA <300 copies/mL, and 27 (96%) achieved confirmed HBeAg loss. All entecavir recipients with HBsAg loss had HBV DNA <300 copies/mL. Caucasian patients, and those infected with HBV genotype A or D, were significantly more likely to lose HBsAg. This retrospective analysis of data from a randomized, global phase three trial shows that confirmed loss of HBsAg occurred in 5% of nucleoside-naïve HBeAg-positive patients treated with entecavir, and that HBsAg loss is associated with sustained off-treatment suppression of HBV DNA.

A longitudinal Raman microspectroscopic study of osteoporosis induced by spinal cord injury

INTRODUCTION

A longitudinal study was established to investigate bone compositional information in spinal cord injury (SCI) rat model.

METHODS

Raman spectroscopy was applied to detect the distal femur and humeri of SCI, sham-operated (SO), and age-matched control (CON) male Sprague-Dawley (SD) rats at first, second, third, and fifth weeks after surgery. One-way ANOVA and Tukey's HSD post hoc multiple comparison tests were used to analyze the longitudinal data of mineral to matrix ratio and carbonate substitution.

RESULTS

Relative mineral decrease was found in SCI group by more than 20% in femur and approximately 12% in humeri compared with CON group. No significant changes in carbonate substitution were observed.

CONCLUSIONS

Severe bone loss in the early stage of SCI was confirmed by a continuous decrease of the mineral to collagen matrix ratio. The decrease in the humeri suggested hormone level variations might participate in the etiology of SCI-induced osteoporosis.

VARS2 V552V Variant as a Prognostic Marker in Patients with Early Breast Cancer

Purpose: The present study analyzed the polymorphisms of DNA repair genes and their impact on survival of patients with early breast cancer.Patients and methods: A total of 240 patients with surgically resected early invasive ductal breast cancer were enrolled in the present study, where patients who underwent neoadjuvant treatment were excluded. The genomic DNA was extracted from paraffin-embedded tumor-free tissue or blood, and thirteen single nucleotide polymorphisms of 12 DNA repair genes were determined using the Sequenom Mass array system.Results: Among the target SNPs, VARS2 rs2074511 and POLE rs5744857 were found to correlate with relapse-free survival (RFS) after curative surgery in the log-rank test. There was no difference in the clinical and tumor characteristics according to the genotypes of these two coding variants except for the higher incidence of positive ER in patients with the GG genotype of POLE rs5744857 (p = 0.025). Multivariate analysis showed that the GG genotype of VARS2 V552V (rs2301717) was marginally associated with a better RFS than the combined AA and AG genotype (HR = 0.298; 95% CI = 0.089-0.995; p = 0.049). However, there was no significant association with overall survival.Conclusion: VARS2 V552V may be considered as a prognostic factor of survival in patients with early breast cancer.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 6055.

Study of the Effect of Micro-Environment Stresses on Breast Tumor Initiating Cells by In Vitro Cell Tracking

Increasing clinical as well as experimental evidence supports the existence of a small population of tumor initiating cells (TIC) that possesses enhanced self-renewal capacity, and the ability to form tumors upon transplantation. These TIC, which highly resemble normal stem cells, are believed to be responsible for tumor initiation and propagation. Evidence also suggests that TIC reside in unique micro-environment which may account for their resistance to traditional chemo- and radiotherapy. Understanding the effect of micro-environment on TIC will have dramatic implications for breast cancer prevention, treatment, and drug development.It is known that tumor micro-environment is characterized by various degrees of chemical imbalance, including oxygen depletion (hypoxia), lactic acidosis, glucose deprivation and high oxidative stresses caused by elevated reactive oxygen species (ROS) [1]. These physiological stresses have significant clinical impact and are often related to poor patient prognosis [2]. Interestingly, recent studies revealed that there are molecular connections between physiological stress regulated transcription factors and pathways known to control stem cell function [3], suggesting that the micro-environment stresses may either promote TIC cell transformation or proliferation [4]. However, despite these molecular level findings, direct evidence on the effect of physiological stresses on the proliferation and differentiation of TIC is still missing.We use in vitro live cell tracking to study the influence of micro-environment on TIC. Primary cultured cells are prepared from breast cancer surgery specimen. They are cultured in suspension in serum free medium as mammospheres which have been demonstrated to be highly enriched with TIC [5]. Various physiological stresses are mimicked by growing cells in tissue culture incubators with 2% O2 (hypoxia), acidic medium (pH 6.7) with 25mM lactic acid, glucose deprivation condition by using glucose free DMEM medium, high ROS condition with 100uM H2O2. Cells are also infected with lentivirus to express H2B-GFP to label the cell nuclei so that they can be tracked by fluorescence imaging. Experiments are carried out in a full environmental controlled (CO2, O2, temperature, humidity) chamber and monitored by confocal imaging over prolonged time up to 96 hours. Since mammosphere cells grow in 3D instead of monolayer, they were scanned by confocal to reconstruct the 3D structure. We also developed computer programs for 3D segmentation to separate each cell, so that each cell within the mammosphere can be labeled and monitored individually. Such system allows us to draw a lineage tree for all the cells in the final mammosphere and detect the active dividing cells (which represent the differentiated cells) and the cells which reenter the quiescent status (which represent the progenitor cells), and hence allow us to study the effect of various micro-environment stresses on them.1. Vaupel, P., Semin Radiat Oncol, 2004. 14(3): p. 198-206.2. Schwickert, G., et al., Cancer Res, 1995. 55(21): p. 4757-9.3. Keith, B. and M.C. Simon, Cell, 2007. 129(3): p. 465-72.4. Li, Z., et al., Cancer Cell, 2009. 15(6): p. 501-13.5. Ponti, D., et al., Cancer Res, 2005. 65(13): p. 5506-11.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 1163.

Amylin suppresses acetic acid-induced visceral pain and spinal c-fos expression in the mouse

Amylin is a member of calcitonin or calcitonin gene-related peptide (CGRP) family. Immunohistochemical study revealed a dense network of amylin-immunoreactive (irAMY) cell processes in the superficial dorsal horn of the mice. Numerous dorsal root ganglion (DRG) and trigeminal ganglion cells expressed moderate to strong irAMY. Reverse transcriptase-polymerase chain reaction (RT-PCR) revealed amylin receptor mRNA in the mouse spinal cord, brain stem, cortex, hypothalamus and hippocampus. The nociceptive or antinociceptive effects of amylin were evaluated in the acetic acid-induced writhing test. Amylin (0.1, 0.5 and 1 mg/kg, intraperitoneally (i.p.) or 1-10 microg, intrathecally (i.t.)) reduced the number of writhes in a dose-dependent manner. Pretreatment of the mice with the amylin receptor antagonist salmon calcitonin (8-32), either by i.p. or i.t., antagonized the effect of amylin on acetic acid-induced writhing test. Locomotor activity was not significantly modified by amylin injected either i.p. (0.01-1 mg/kg) or i.t. (1-10 microg). Measurement of c-fos mRNA by RT-PCR or proteins by Western blot showed that the levels were upregulated in the spinal cord of mice injected with acetic acid and the increase was attenuated by pretreatment with amylin (10 microg, i.t.). Collectively, our result demonstrates that irAMY is expressed in DRG neurons with their cell processes projecting to the superficial layers of the dorsal horn, and that the peptide by interacting with amylin receptors in the spinal cord may be antinociceptive.

Paradoxical functions of B7: CD28 costimulation in a MHC class II-mismatched cardiac transplant model

Blockade of the B7: CD28 costimulatory pathway has emerged as a promising therapy to prevent allograft rejection. However, this pathway has also been demonstrated to be important for the generation and maintenance of regulatory T cells. In this study, we investigated the role of the B7: CD28 pathway in the 'bm12 into B6' MHC class II-mismatched vascularized cardiac transplant model of chronic rejection. Allograft rejection was remarkably accelerated in B6 background B7DKO and CD28KO recipients compared with B6 wild-type (WT) recipients. Allograft rejection was associated with a significantly enhanced Th1/Th2 alloreactivity and marked reduction in the ratio of regulatory T cells to CD4(+) effector/memory cells. We noted that administration of anti-B7-1 and anti-B7-2 mAb prior to transplantation also accelerated allograft rejection. Furthermore, depleting CD25(+) cells in B6 WT recipients of bm12 hearts prior to transplant also precipitated rejection at a similar rate. Neither B7/CD28 deficiency nor CD25 depletion affected graft survival in single MHC class I-mismatched (bm1 into B6) recipients. This study highlights the paradoxical functions of B7: CD28 costimulation in a MHC class II-mismatched model, in which the B7: CD28 pathway is demonstrated to be important in preventing rejection through the generation and maintenance of Tregs.

Validity of interferon-γ-release assays for the diagnosis of latent tuberculosis in haemodialysis patients

Haemodialysis patients are at higher risk of developing active tuberculosis (TB) infection. However, tuberculin skin tests (TST) have limitations and the diagnostic usefulness of interferon-γ-release assays (IGRAs) remains unclear in immunocompromised hosts including haemodialysis patients. Haemodialysis patients were enrolled from a dialysis centre in Korea, an intermediate TB-burden country with a high bacille Calmette-Guérin (BCG) vaccination rate. The QuantiFERON-Gold TB In tube test (QFT) and the T-SPOT TB test (TSPOT) were performed, along with the TST. We stratified patients to low- and high-risk groups, according to the risk factors for latent TB. Association between each of the three diagnostic tests and the risk of latent TB was analysed. One hundred and sixty-seven patients were enrolled. The positive rates for the TST, the QFT and TSPOT were 23.5, 45.9 and 60.4%, respectively. Previous BCG vaccination increased the TST-positive rate in the low-risk group (OR 4.438), whereas it affected neither QFT nor TSPOT. The positive QFT rates were 41.2 and 62.5% in the low- and high-risk groups, respectively. The QFT was associated with the high-risk group (OR 2.578), whereas the TST was not. The positive TSPOT rates were 58.9 and 65.7% in the low- and high-risk groups, respectively. The frequency of indeterminate results was higher for the QFT (12.6%) compared with the TSPOT (4.8%). In conclusion, the IGRAs can be useful for the diagnosis of latent TB infection in haemodialysis patients.

Physician's practice patterns for chronic prostatitis

Chronic prostatitis (CP) is one of the most prevalent conditions in urology, yet the most poorly understood. Although there is little controversy regarding the therapy for documented acute bacterial infections, most symptomatic men do not have bacterial prostatitis, for which treatment and management are usually successful. Throughout the past century, the diagnostic entity of CP has been recognised and its clinical characteristics have been well described. However, no hard and fast guidelines have been developed. To date, several surveys of physicians have been undertaken in order to examine their practice characteristics, attitude, diagnostics and treatment modalities applied in patients with CP. These surveys demonstrate that physicians show large deficits in familiarity with and knowledge of CP along with significant uniformity in the medical approach to this condition and confirm the frustration experienced by physicians in the management of this disease. The results of these studies also suggest an important role for continuing education on the diagnosis and treatment of CP. Further study is needed to identify the aetiology and pathogenesis of male chronic pelvic pain and to establish guidelines for its diagnosis and treatment.

Role of hypoxia-inducible factor-1 alpha in the regulation of plasminogen activator activity in rat knee joint chondrocytes

OBJECTIVE

To examine the effects of hypoxia-inducible factor-1alpha (HIF-1alpha) on the plasminogen activator's (PA) activity and on the expression of components of PA system in articular chondrocytes of rats.

METHODS

Chondrocytes from rat knee joint cartilage were cultured under normoxic, hypoxic, CoCl(2) simulated hypoxic, and interleukin-1beta (IL-1beta)-stimulated conditions. siRNA targeting HIF-1alpha was transfected into cells cultured under hypoxic, simulated hypoxic, and IL-1beta-stimulated conditions to silence HIF-1alpha. PA activity was determined by the hydrolysis of the chromogenic substrate H-D-Val-Leu-Lys-pNA (S-2251). The mRNA levels were measured by quantitative real-time reverse transcription polymerase chain reaction (RT-PCR). The intracellular/matrix-associate protein levels were detected by Western blot and the soluble protein levels were measured by enzyme linked immunosorbent assay (ELISA). Chromatin immunoprecipitation (CHIP) assay was performed to determine whether HIF-1alpha binds to the hypoxia response element (HRE) of target genes.

RESULTS

The enhancement of HIF-1alpha by CoCl(2) resulted in a decrease of PA activity, and the silence of HIF-1alpha by siRNA led to an increase of PA activity. The PA inhibitor-1 (PAI-1) mRNA and protein were increased by hypoxia or simulated hypoxia, which was reversed by the siRNA2-mediated silencing of HIF-1alpha. CHIP assay further confirmed that the induction of PAI-1 involved the binding of HIF-1alpha to the PAI-1 promoter, while the enhancement or silencing of HIF-1alpha did not affect the expression of urokinase type PA (uPA), tissue type PA (tPA) or uPA receptor (uPAR). Additionally, IL-1beta stimulated both HIF-1alpha and PAI-1 in articular chondrocytes, and the IL-1beta-mediated induction of PAI-1 was inhibited partly by HIF-1alpha silencing.

CONCLUSION

HIF-1alpha may inhibit the PA activity through stimulating the expression of PAI-1 in normal articular chondrocytes. The inhibition of HIF-1alpha in the PA activity of articular chondrocytes probably plays an important role in the maintenance of articular cartilage matrix.

Hypermethylation of HLA class I gene is associated with HLA class I down-regulation in human gastric cancer

Down-regulated expression of human leukocyte antigen (HLA) class I molecules in many human cancers facilitate tumor cells to escape from immune attack. Promoter hypermethylation, one of the major epigenetic changes responsible for gene inactivation, plays an important role in gastric carcinogenesis. This study evaluated the expression and alteration of HLA class I molecules in a panel of 47 pairs of gastric cancer specimens with their noncancerous parts from Chinese patients by using immunohistochemistry (IHC), reverse transcription polymerase chain reaction (RT-PCR) and methylation-specific PCR (MSP) analysis. The expression of HLA-A, HLA-B/C and HLA class I complex was lost or down-regulated in human gastric cancer. The percentage of promoter methylation was 59.57% for HLA-A gene, 55.32% for HLA-B gene and 48.94% for HLA-C gene in gastric cancer, while it was decreased to 19.15%, 12.77% and 6.38% in the adjacent nontumor tissues, respectively. Seven of 10 (70%), 4 of 6 (66.7%) and 3 of 4 (75%) gastric cancer specimens with promoter hypermethylation at HLA-A, -B and -C loci showed transcriptional inactivation of HLA-A,-B and -C genes, suggesting an association between promoter hypermethylation and down-regulated expression of HLA class I molecules. Human gastric cancer cell line BGC-823 showed HLA-A down-regulation with promoter methylation of HLA-A locus. Treatment with DNA methyltransferase inhibitor restored the expression of HLA-A mRNA and surface HLA-A complex. Thus, our results showed that promoter hypermethylation might be one of the mechanisms that lead to HLA class I antigen down-regulation in gastric cancer.

Synergistic effect in treatment of C.I. Acid Red 2 by electrocoagulation and electrooxidation

An aqueous C.I. Acid Red 2 solution was decolorized by electrolysis using iron as anode. The decolorization mechanism was investigated through experimental observations on the electrochemical behavior of C.I. Acid Red 2 on Pt rotating disk electrode, UV-visible spectra of the solution and IR spectra of the coagulated mixtures. It is found that the decolorization efficiency is high, over 98.0% after 40 min, and this high decolorization efficiency can be ascribed to the synergistic effect of electrocoagulation and electrooxidation. The electrocoagulation results from the electrogenerated iron hydroxide and the electrooxidation results from electrogenerated ferric ions. The results obtained from IR spectra shows that the decolorization of C.I. Acid Red 2 by electrooxidation is due to the partial or complete cleavage of C-N bonds in C.I. Acid Red 2.

Hyperhomocysteinaemia, low folate concentrations and methylene tetrahydrofolate reductase C677T mutation in acute mesenteric venous thrombosis

OBJECTIVES

Acute mesenteric venous thrombosis (AMVT) was first reported by Fagge and was recognised as a distinct clinical entity by Warreen in 1935. However, its pathogenesis is still unclear. Elevated plasma levels of homocysteine (Hcy) are associated with an increased risk of deep vein thrombosis. This case-control study examines the potential association among hyperhomocysteinaemia (hyper-Hcy), low serum folate and vitamin B(12) levels and the common C677T mutation of the MTHFR gene in patients with AMVT.

MATERIALS AND METHODS

Sixty-three patients with AMVT and 75 sex- and age-matched healthy controls were recruited, and their plasma Hcy, folate and vitamin B(12) levels were measured by high performance liquid chromatography (HPLC) and immunological assays. The polymorphism of MTHFR C677T was detected by PCR-RFLP.

RESULTS

The mean plasma Hcy levels were significantly higher in patients with AVMT compared with controls (23.5 standard deviation (S.D.) 8.8 vs. 12.6+/-6.6micromoll(-1), P<0.01). The fasting Hcy correlated negatively with folate (AMVT: r=-0.42, P<0.01;

CONTROL

r=-0.40, P<0.01). The frequency of homozygous (TT) genotype in MTHFR C677T mutation was significantly higher in patients with AMVT than that in control subjects (33% vs. 17%; chi square (chi(2))=6.31, P<0.05; odds ratio (OR)=2.80; 95% confidence interval (CI): 1.25-6.25). Compared with the control subjects, the mean serum vitamin B(12) levels were lower in patients, but it was not statistically significant (365+/-88pmoll(-1) vs. 408+/-108pmoll(-1), P>0.05).

CONCLUSIONS

Hyper-Hcy and low serum folate levels were associated with an increased risk of AMVT. The homozygous (TT) genotype of MTHFR gene mutation may be a crucial hereditary risk factor in the development of AMVT for a Chinese population.

Cells deficient in the base excision repair protein, DNA polymerase beta, are hypersensitive to oxaliplatin chemotherapy

A significant proportion of human cancers overexpress DNA polymerase beta (Pol beta), the major DNA polymerase involved in base excision repair. The underlying mechanism and biological consequences of overexpression of this protein are unknown. We examined whether Pol beta, expressed at levels found in tumor cells, is involved in the repair of DNA damage induced by oxaliplatin treatment and whether the expression status of this protein alters the sensitivity of cells to oxaliplatin. DNA damage induced by oxaliplatin treatment of HCT116 and HT29 colon cancer cells was observed to be associated with the stabilization of Pol beta protein on chromatin. In comparison with HCT116 colon cancer cells, isogenic oxaliplatin-resistant (HCT-OR) cells were found to have higher constitutive levels of Pol beta protein, faster in vitro repair of a DNA substrate containing a single nucleotide gap and faster repair of 1,2-GG oxaliplatin adduct levels in cells. In HCT-OR cells, small interfering RNA knockdown of Pol beta delayed the repair of oxaliplatin-induced DNA damage. In a different model system, Pol beta-deficient fibroblasts were less able to repair 1,2-GG oxaliplatin adducts and were hypersensitive to oxaliplatin treatment compared with isogenic Pol beta-expressing cells. Consistent with previous studies, Pol beta-deficient mouse fibroblasts were not hypersensitive to cisplatin treatment. These data provide the first link between oxaliplatin sensitivity and DNA repair involving Pol beta. They demonstrate that Pol beta modulates the sensitivity of cells to oxaliplatin treatment.

Defective plasmacytoid dendritic cell-NK cell cross-talk in HIV infection

HIV viremia is associated with a wide range of immune dysfunctions that contribute to the immunocompromised state. HIV viremia has been shown to have a broad effect on several immune cell types and/or their interactions that are vital for mounting an effective immune response. In this study, we investigated the integrity of plasmacytoid dendritic cell (pDC)-NK cell interactions among HIV viremic, aviremic, and seronegative individuals. We describe a critical defect in the ability of pDCs from HIV-infected individuals to secrete IFN-alpha and TNF and subsequently activate NK cells. We also describe an inherent defect on NK cells from HIV-infected individuals to respond to pDC-secreted cytokines. Furthermore, we were able to demonstrate a direct effect of HIV trimeric gp120 on NK cells in vitro similar to that described ex vivo. Finally, we were able to establish that the HIV gp120-mediated suppressive effect on NK cells was a result of its binding to the integrin alpha(4)beta(7) expressed on NK cells. These findings suggest a novel mechanism by which HIV is capable of suppressing an innate immune function in infected individuals.