Essential roles of Jab1 in cell survival, spontaneous DNA damage and DNA repair

Jun activation domain-binding protein 1 (JAB1) is a multifunctional protein that participates in the control of cell proliferation and the stability of multiple proteins. JAB1 overexpression has been implicated in the pathogenesis of human cancer. JAB1 regulates several key proteins and thereby produces varied effects on cell cycle progression, genome stability and cell survival. However, the biological significance of JAB1 activity in these cellular signaling pathways is unclear. Therefore, we developed mice that were deficient in Jab1 and analyzed the null embryos and heterozygous cells. This disruption of Jab1 in mice resulted in early embryonic lethality due to accelerated apoptosis. Loss of Jab1 expression sensitized both mouse primary embryonic fibroblasts and osteosarcoma cells to γ-radiation-induced apoptosis, with an increase in spontaneous DNA damage and homologous recombination (HR) defects, both of which correlated with reduced levels of the DNA repair protein Rad51 and elevated levels of p53. Furthermore, the accumulated p53 directly binds to Rad51 promoter, inhibits its activity and represents a major mechanism underlying the HR repair defect in Jab1-deficient cells. These results indicate that Jab1 is essential for efficient DNA repair and mechanistically link Jab1 to the maintenance of genome integrity and to cell survival.

Autism spectrum disorder is related to endoplasmic reticulum stress induced by mutations in the synaptic cell adhesion molecule, CADM1

Autism spectrum disorder (ASD) is a neurodevelopmental disorder with an unknown molecular pathogenesis. A recent molecular focus has been the mutated neuroligin 3, neuroligin 3(R451C), in gain-of-function studies and for its role in induced impairment of synaptic function, but endoplasmic reticulum (ER) stress induced by mutated molecules also deserves investigation. We previously found two missense mutations, H246N and Y251S, in the gene-encoding synaptic cell adhesion molecule-1 (CADM1) in ASD patients, including cleavage of the mutated CADM1 and its intracellular accumulation. In this study, we found that the mutated CADM1 showed slightly reduced homophilic interactions in vitro but that most of its interactions persist. The mutated CADM1 also showed morphological abnormalities, including shorter dendrites, and impaired synaptogenesis in neurons. Wild-type CADM1 was partly localized to the ER of C2C5 cells, whereas mutated CADM1 mainly accumulated in the ER despite different sensitivities toward 4-phenyl butyric acid with chemical chaperone activity and rapamycin with promotion activity for degradation of the aggregated protein. Modeling analysis suggested a direct relationship between the mutations and the conformation alteration. Both mutated CADM1 and neuroligin 3(R451C) induced upregulation of C/EBP-homologous protein (CHOP), an ER stress marker, suggesting that in addition to the trafficking impairment, this CHOP upregulation may also be involved in ASD pathogenesis.

Con-specific neighbours may enhance compensation capacity in an invasive plant

Facilitation, both by inter- and intra-specific neighbours, is known to be an important process in structuring plant communities. However, only a small number of experiments have been reported on facilitation in plant invasions, especially between invasive con-specific individuals. Here, we focus on how con-specific neighbours of the invasive alien plant alligator weed affect the tolerance of alligator weed to herbivory by the introduced biological control agent, Agasicles hygrophila. We conducted greenhouse and garden experiments in which invasive plant density and herbivory intensity (artificial clipping and real herbivory) were manipulated. In the greenhouse experiment, artificial clipping significantly reduced plant biomass when plants were grown individually, but when con-specific neighbours were present in the same pot, biomass was not significantly different from control plants. Similarly, when compared to control plants, plants that were subjected to herbivory by A. hygrophila produced more biomass when grown with two con-specific neighbours than when grown alone. Real herbivory also resulted in an increased number of vegetative buds, and again when two con-specific neighbours were present this effect was increased (a 55.3% increase in buds when there was no neighbour, but a 111.6% increase in buds when two con-specific neighbours were present). In the garden experiment, in which plants were grown at high density (6 plants per pot), alligator weed fully recovered from defoliation caused by insects at levels from 20-30% to 100%. Our results indicate that the con-specific association may increase the compensatory ability to cope with intense damage in this invasive plant.

Elevated levels of serum antibodies against Saccharomyces cerevisiae mannan in patients with systemic lupus erythematosus

This study was undertaken to investigate whether levels of anti- Saccharomyces cerevisiae mannan antibodies (ASCMAs), a serological marker for Crohn’s disease, seronegative spondyloarthritis and Behcet’s disease, also correlate with systemic lupus erythematosus (SLE) in humans. Serum samples from healthy volunteers ( n = 152) and patients with SLE ( n = 40) were compared for ASCMA-IgA, -IgG and -IgM levels using enzyme linked immunosorbent assays. ASCMA-IgG, but not IgM and IgA, prevalence was significantly raised in active SLE patients (57.5%) compared with healthy controls (8.5%). ASCMA-IgG levels in SLE patients during remission were relatively lower, indicating a possible correlation with disease activity. These results differ from a previous study, which did not detect a difference between ASCMA levels in SLE patients and healthy control. It remains to be evaluated whether elevated ASCMA-levels are common to all rheumatic disorders.

Cloning, mapping and mutation analysis of human geneGJB5 encoding gap junction protein beta-5

By homologous EST searching and nested PCR a new human geneGJB5 encoding gap junction protein beta-5 was identified.GJB5 was genetically mapped to human chromosome 1p33-p35 by FISH. RT-PCR revealed that it was expressed in skin, placenta and fetal skin. DNA sequencing ofGJB5 was carried out in 142 patients with sensorineural hearing impairment and probands of 36 families with genetic diseases, including erythrokeratodermia (5 families), Charcot-Marie-Tooth disease (13), ptosis (4), and retinitis pigmentosa and deafness (14). Two missense mutations (686A-->G, H229R; 25C-->T, L9F) were detected in two sensorineural hearing impairment families. A heterologous deletion of 18 bp within intron was found in 3 families with heredity hearing impairment, and in one of the 3 families, a missense mutation (R265P) was identified also. But the deletion and missense mutation seemed not segregating with hearing impairment in the family. No abnormal mRNA or mRNA expression was detected in deletion carriers by RT-PCR analysis in skin tissue. Mutation analysis in 199 unaffected individuals revealed that two of them were carriers with the same 18 bp deletion.

Noninvasive Raman spectroscopy in living mice for evaluation of tumor targeting with carbon nanotubes

An optimized noninvasive Raman microscope was used to evaluate tumor targeting and localization of single walled carbon nanotubes (SWNTs) in mice. Raman images were acquired in two groups of tumor-bearing mice. The control group received plain-SWNTs, whereas the experimental group received tumor targeting RGD-SWNTs intravenously. Raman imaging commenced over the next 72 h and revealed increased accumulation of RGD-SWNTs in tumor ( p < 0.05) as opposed to plain-SWNTs. These results support the development of a new preclinical Raman imager.

Neolysogenization of Xanthomonas campestris pv. citri infected with filamentous phage Cf16

All previously described filamentous bacteriophages are capable of persistent infection while their DNA replicates as an episome in the host cell. Filamentous phage Cf16 undergoes an infectious cycle different from other filamentous phages reported heretofore. Upon initial infection with Cf16, infective centers are formed, each of which produces a large number of phage particles. As the infectious cycle progresses, the phage particles released and infective centers formed per carrier cell decrease with time. Finally, the Cf16 enters a "prophage" state, in which the carrier cell becomes lysogenic containing only one complete phage genome in an integrated form. One out of 10(3)-10(6) lysogenic cells can develop spontaneously into an infective center, which releases only one to two phage particles per cell in stationary phase culture. After infection, the Cf16 genome integrates into the host chromosome and replicates as a part of it. Free RF (replicative form) coexists with the integrated form and replicates independently from host chromosome. Upon further division, carrier cells eliminate the free RF at each succeeding generation. When Cf16 reaches the "prophage" state, only the integrated phage genome remains in the carrier cell with no detectable free RF.

The lysogenic cycle of the filamentous phage Cflt from Xanthomonas campestris pv. citri

A phage, Cflt, forming turbid plaques, was isolated from Xanthomonas campestris pv. citri. After infection, infected sensitive cells become immune to Cflt and produce very few phages. These properties were genetically rather stable. The phage was purified and shown to be filamentous with a size of 1157 +/- 73 nm. The genome size is about 7.62 kb. The phage does not affect the growth of host bacteria. Under natural cultivation conditions Cflt-lysogenized cells could be induced spontaneously to give high phage yields, or cured to give phage-free cells. The integration of Cflt DNA into host DNA was proved by Southern blot hybridization. The lysogenic phage was genetically stable in log phase cells and persisted in stationary phase cells through many cell generations in the absence of extracellular phage reinfection.

A five-year follow-up study of goiter and thyroid nodules in three regions with different iodine intakes in China

OBJECTIVE

The association between iodine status and the prevalence of goiter and thyroid nodules has been well established but the extent to which different iodine intake levels influence the incidence of goiter and thyroid nodules is unclear. The aim of the study was to determine the incidence of goiter and thyroid nodules in 3 regions with different iodine intake levels: mildly deficient, more than adequate, and excessive.

DESIGN, PATIENTS AND MEASUREMENTS

Of the 3385 unselected subjects enrolled in 1999 in Panshan, Zhangwu, and Huanghua where median urinary iodine excretion (UIE) was 83.5 microg/l, 242.9 microg/l, and 650.9 microg/l, respectively, 2708 (80.0%) participated in the follow-up study in 2004. The examinations of thyroid ultrasonography, thyroid function, thyroid autoantibodies and UIE were performed at baseline and follow-up.

RESULTS

The cumulative incidence of diffuse goiter was 7.1%, 4.4%, and 6.9%, respectively, higher in Panshan and Huanghua than in Zhangwu (p=0.013 and p=0.015) and that of nodular goiter was 5.0%, 2.4%, and 0.8%, respectively, declining with increasing iodine intake levels (p<0.001). Mild iodine deficiency, chronic iodine excess as well as positive thyroid autoantibodies were associated with the occurrence of goiter [Logistic regression: odds ratio (OR)=1.83 (95% confidence interval (CI) 1.26-2.65), OR=1.46 (95% CI 1.01-2.11) and OR=1.68 (95% CI 1.14-2.48), respectively]. The cumulative incidence of single nodule was 4.0%, 5.7%, and 5.6%, respectively and that of multiple nodules was 0.4%, 1.2%, and 1.0%, respectively.

CONCLUSIONS

The relationship between iodine and the risk for the occurrence of diffuse goiter shows a U-shaped curve. Nodular goiters are more prevalent in iodine-deficient areas.

Moment switching in nanotube magnetic force probes

Magnetic images of high density vertically recorded media using metal-coated carbon nanotube tips exhibit a doubling of the spatial frequency under some conditions (Deng et al 2004 Appl. Phys. Lett. 85 6263). Here we demonstrate that this spatial frequency doubling is due to the switching of the moment direction of the nanotube tip. This results in a signal which is proportional to the absolute value of the signal normally observed in MFM. Our modeling indicates that a significant fraction of the tip volume is involved in the observed switching, and that it should be possible to image high bit densities with nanotube magnetic force sensors.

Neutralizing IL-7 promotes long-term allograft survival induced by CD40/CD40L costimulatory blockade

Memory T cells are somewhat resistant to immunosuppresion. They therefore pose a threat to inducing long-term allograft survival. IL-7 is essential for memory T-cell generation. Here, we investigated whether neutralizing IL-7 promotes allograft survival. We found that neutralizing IL-7 alone did not significantly prolong allograft survival. However, blocking both IL-7 and CD154 signaling synergistically prolonged allograft survival. In contrast, neutralizing IL-2 failed to further prolong allograft survival induced by CD40/CD154 costimulatory blockade. Allospecific memory CD8+ T-cell generation was severely impaired under the treatment of anti-IL-7 plus anti-CD154 Ab while administering recombinant IL-7 enhanced CD8+ memory generation even under donor-specific transfusion plus anti-CD154 Ab treatment. Neutralizing IL-7, but not IL-2, together with blocking CD154 synergistically suppressed the proliferation of naïve/effector CD8+ T cells infiltrating grafts. Nevertheless, neutralizing IL-7 did not alter regulatory T-cell generation while neutralizing IL-2 suppressed their generation. Hence, targeting IL-7 represents a new strategy to prolong allograft survival by acting on both naïve and memory T cells. Long-term allograft survival may be achieved by neutralizing IL-7 plus CD40/CD154 blockade, since CD40/CD154 costimulatory blockade prevents acute rejection while neutralizing IL-7 suppresses the generation of memory T cells that persist and mediate late or chronic rejection.

Circulating levels of the breast cancer growth factor GP88 in the serum of breast cancer (BC) patients

20050

Background: The 88 kDa autocrine growth factor PC-Cell Derived Growth Factor (GP88) plays a critical role in breast tumorigenesis. GP88 expression was low in estrogen receptor positive cells, whereas in ER negative cells, it was constitutively overexpressed. Increased GP88 expression was associated with anti-estrogen therapy resistance in ER+ cells and Herceptin resistance in Her-2 overexpressing breast tumors. Antisense inhibition of GP88 expression in human breast adenocarcinoma lead to inhibition of tumor growth in vivo. Immunohistochemical studies have shown that GP88 was expressed in 80% of invasive ductal carcinomas in correlation with expression of poor prognosis markers whereas normal tissues and benign breast lesions were negative. Since GP88 is secreted by breast cancer cells, we examined whether GP88 was found in the circulation at an elevated level in the sera of breast cancer patients when compared to healthy individuals. Methods: A blood sampling study was conducted to determine the serum level of GP88 in healthy volunteers (HV) and breast cancer patients (BC pts). Ten ml of blood was drawn every three months to obtain serum. GP88 serum concentration was determined in triplicate by quantitative enzyme immunoassay using human GP88 as standard. 126 BC pts were accrued. . In addition, sera from 53 healthy volunteers were obtained to establish a GP88 baseline in HV. BC pts characteristics: race: Caucasian- 61, African American-60, Asian-5; median age: 52.5 (range 26–84), stage I-32, II-34, III-18, IV-42. Results: Circulating GP88 was measurable in the serum. Median level of GP88 was 32.8 ng/ml (range 15.3–42.8) in HV and 43.8 ng/ml (range 15.4–158.4) in BC pts, (p-value = 0.0007). Conclusions: GP88 is measurable in the sera of HV and BC pts. Comparison between the two groups indicates that GP88 level is significantly higher in the sera of BC pts. These studies are important since it identifies GP88 as a measurable biomarker that is also a therapeutic target of malignant transformation or malignant progression of breast carcinoma (BC). Future studies will examine the correlation of GP88 level with BC prognostic factors. Correlation between the serum level of GP88 and therapeutic response to systemic therapy in breast cancer patients will also be assessed.

[Table: see text]

An RT-PCR-based multi-gene prognostic signature predicts distant metastasis of node negative, ER positive breast cancer from FFPE sections

506

Background: Gene expression profiles have been shown to predict distant metastasis risk in breast cancer patients. For routine medical practice, molecular prognostic tests need to be able to quantify metastasis risk with readily available samples and optimally employ regulatory-approved platforms. Methods: 142 early stage, N-, ER+, untreated breast cancer patients were chosen. Mean age was 61.8 (31 - 89) yrs with 72% > 55 yrs. RNA was isolated from 4×10 μm FFPE sections. Using real-time RT-PCR, 200 genes selected from van ‘t Veer et al, Dai et al, Paik et al and additional candidate genes were profiled. Primary endpoint was distant metastasis free survival. A prognostic signature was identified using semi-supervised principal component method. Metastasis score (MS) was calculated from gene expression levels. Results: We identified a unique 15-gene prognostic signature and 3 normalization genes. Probability of metastasis for any time period can be calculated from MS and was evaluated for 2, 5, and 10 yrs. Using median of MS to stratify patients, the high-risk group had a hazard ratio (HR) of 4.1 (95%CI 1.77–9.54, p = 0.001) vs. the low-risk group. 5-yr and 10-yr metastasis free survival rates (std. error) were 0.76 (0.053) and 0.62 (0.064) in the high-risk group and 0.96 (0.025) and 0.90 (0.038) in the low-risk group. Multivariate Cox regression analyses indicated that molecular signature had independent prognostic value with HR of 2.97 (95%CI 1.17 - 7.52, p = 0.022) after adjusting for age, tumor size and grade. Molecular signature was more prognostic in the low-grade subgroup (HR = 6.85, 95%CI 1.81–25.88) than an unstratified analysis. AUC at 5 yr was 0.65 and 0.60 for molecular signature and Adjuvant Online (AO) respectively. The prognosticator combining both had AUC of 0.67. 10-yr metastasis probabilities from MS and AO have low correlation (R2=0.17). Conclusions: A prognostic signature based upon mRNA expression of 15 genes has been identified using FFPE sections with RT-PCR for early stage, N-, ER+ patients. Metastasis score that quantifies distant metastasis risk for any time period, not confounded with any treatment effect, can help clinicians and patients to choose among different therapeutic options. (Lau and Wang contribute equally)

[Table: see text]

Hydrogenation of single-walled carbon nanotubes

Towards the development of a useful mechanism for hydrogen storage, we have studied the hydrogenation of single-walled carbon nanotubes with atomic hydrogen using core-level photoelectron spectroscopy and x-ray absorption spectroscopy. We find that atomic hydrogen creates C-H bonds with the carbon atoms in the nanotube walls, and such C-H bonds can be completely broken by heating to 600 degrees C. We demonstrate approximately 65 +/- 15 at % hydrogenation of carbon atoms in the single-walled carbon nanotubes, which is equivalent to 5.1 +/- 1.2 wt % hydrogen capacity. We also show that the hydrogenation is a reversible process.

No common denominator for breast cancer lymph node metastasis

The axillary lymph node status is the most powerful prognostic factor for breast cancer patients to date. The molecular mechanisms that control lymph node metastasis, however, remain poorly understood. To define patterns of genes or gene regulatory pathways that drive breast cancer lymph node metastasis, we compared the gene expression profiles of 15 primary breast carcinomas and their matching lymph node metastases using microarrays. In general, primary breast carcinomas and lymph node metastases do not differ at the transcriptional level by a common subset of genes. No classifier or single gene discriminating the group of primary tumours from those of the lymph node metastases could be identified. Also, in a series of 295 breast tumours, no classifier predicting lymph node metastasis could be developed. However, subtle differences in the expression of genes involved in extracellular-matrix organisation and growth factor signalling are detected in individual pairs of matching primary and metastatic tumours. Surprisingly, however, different sets of these genes are either up- or downregulated in lymph node metastases. Our data suggest that breast carcinomas do not use a shared gene set to accomplish lymph node metastasis.

Measurement of the flux of ultrahigh energy cosmic rays from monocular observations by the High Resolution Fly's Eye experiment

We have measured the cosmic ray spectrum above 10(17.2) eV using the two air-fluorescence detectors of the High Resolution Fly's Eye observatory operating in monocular mode. We describe the detector, phototube, and atmospheric calibrations, as well as the analysis techniques for the two detectors. We fit the spectrum to a model consisting of galactic and extragalactic sources.