HER2 signaling modulates the equilibrium between pro- and antiangiogenic factors via distinct pathways: implications for HER2-targeted antibody therapy

We determined the impact of HER2 signaling on two proangiogenic factors, vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), and on an antiangiogenic factor, thrombospondin-1 (TSP-1). Re-expression of HER2 in MCF-7 and T-47D breast cancer cells that endogenously express low levels of HER2 resulted in elevated expression of VEGF and IL-8 and decreased expression of TSP-1. Inhibition of HER2 with a humanized anti-HER2 antibody (trastuzumab, or Herceptin) or a retrovirus-mediated small interfering RNA against HER2 (siHER2) decreased VEGF and IL-8 expression, but increased TSP-1 expression in BT474 breast cancer cells that express high levels of HER2. These in vitro results were further evaluated by treatment of BT474 xenografts in immunosuppressed mice with trastuzumab. Trastuzumab inhibited growth of BT474 xenografts and decreased microvascular density associated with downregulation of VEGF and IL-8 and with upregulation of TSP-1 expression. Inhibiting the PI3K-AKT pathway decreased VEGF and IL-8 expression. AKT1 overexpession increased VEGF and IL-8 expression, but did not increase TSP-1 expression. A p38 kinase inhibitor, SB203580, instead blocked TSP-1 expression and a p38 activator, MKK6, increased TSP-1 expression. Trastuzumab stimulated sustained p38 activation and SB203580 attenuated the TSP-1 upregulation induced by trastuzumab. HER2 signaling therefore influences the equilibrium between pro- and antiangiogenic factors via distinct signaling pathways. Trastuzumab inhibits angiogenesis and tumor growth, at least in part, through activation of the HER2-p38-TSP-1 pathway and inhibition of the HER2-PI3K-AKT-VEGF/IL-8 pathway.

Spine loading as a function of lift frequency, exposure duration, and work experience

BACKGROUND

Physiological and psychophysical studies of the effects of lifting frequency have focused on whole-body measurements of fatigue or subjective acceptance of the task and have not considered how spine loads may change as a function of lift frequency or lift time exposure. Our understanding of biomechanical spine loading has been extrapolated from short lifting bouts to the entire work day and may have led us to incorrect assumptions. The objective of this project was to document how spine loading changes as a function of experience, lift frequency, and lift duration while repetitively lifting over the course of an 8-h workday.

METHODS

Twelve novice and twelve experienced manual materials handlers performed repetitive, asymmetric lifts at different load and lift frequency levels throughout an 8-h exposure period. Compression, anterior-posterior shear, and lateral shear were evaluated over the lifting period using an EMG-assisted biomechanical model.

RESULTS

Spinal loads increased after the first 2 h of lifting exposure regardless of the lift frequency. Loading was also greater for the inexperienced subjects compared to experienced lifters. The greatest spine loads occurred at those lift frequencies and weights to which the workers were unaccustomed.

INTERPRETATION

Increases in spine loading were tracked back to the changes in muscle recruitment patterns that typically involved increased muscle coactivation. The results emphasize the importance of previous motor programming in defining spine loads during repetitive lifting. These results indicate a very different influence of frequency and lift time exposure compared to physiologic and psychophysical assessments. This study has shown that it is not sufficient to extrapolate from short lift periods to extended exposure periods if the biomechanical loading implications of the task are of interest.

Photorhabdus virulence cassettes confer injectable insecticidal activity against the wax moth

Two recently sequenced genomes of the insect-pathogenic bacterium Photorhabdus and a large Serratia entomophila plasmid, pADAP, have phage-related loci containing putative toxin effector genes, designated the "Photorhabdus virulence cassettes" (PVCs). In S. entomophila, the single plasmid PVC confers antifeeding activity on larvae of a beetle. Here, we show that recombinant Escherichia coli expressing PVC-containing cosmids from Photorhabdus has injectable insecticidal activity against larvae of the wax moth. Electron microscopy showed that the structure of the PVC products is similar to the structure of the antibacterial R-type pyocins. However, unlike these bacteriocins, the PVC products of Photorhabdus have no demonstrable antibacterial activity. Instead, injection of Photorhabdus PVC products destroys insect hemocytes, which undergo dramatic actin cytoskeleton condensation. Comparison of the genomic organizations of several PVCs showed that they have a conserved phage-like structure with a variable number of putative anti-insect effectors encoded at one end. Expression of these putative effectors directly inside cultured cells showed that they are capable of rearranging the actin cytoskeleton. Together, these data show that the PVCs are functional homologs of the S. entomophila antifeeding genes and encode physical structures that resemble bacteriocins. This raises the interesting hypothesis that the PVC products are bacteriocin-like but that they have been modified to attack eukaryotic host cells.

Adenoviral vector-mediated RTVP-1 gene-modified tumor cell-based vaccine suppresses the development of experimental prostate cancer

We previously identified a novel p53 target gene, RTVP-1, that possesses unique cytotoxic and immunostimulatory activities which make it potentially useful for cancer gene therapy. To test the therapeutic potential of RTVP-1 in a gene-modified tumor cell-based vaccine model, we used an adenoviral vector capable of efficient transduction and expression of RTVP-1 (AdRTVP-1), together with a highly metastatic mouse prostate cancer cell line (178-2 BMA). A vaccine was prepared with 178-2 BMA cells transduced with AdRTVP-1 or a control adenoviral vector expressing beta-galactosidase (Adbetagal). After irradiation of the cells, syngeneic 129/Sv mice were vaccinated three times at weekly intervals. After 3 weeks, they were challenged with orthotopic 178-2 BMA cells. After 21 days, fewer than 60% of the RTVP-1-cell-vaccinated mice developed tumors compared to 100% of the control mice. The RTVP-1-cell vaccine significantly reduced primary tumor wet weight compared with control Adbetagal-cell vaccine (P<0.0001 at 7 and 14 days). Experimental metastasis to lung was also significantly reduced (P=0.0377), and survival significantly increased (P=0.0002). In addition, significantly increased NK and CTL activities were demonstrated in the AdRTVP-1-cell-vaccinated mice. These findings indicate that RTVP-1 gene-modified cell-based vaccines may be useful in the prevention of recurrent prostate cancer.

Use of body mass index to identify obesity-related metabolic disorders in the Chinese population

OBJECTIVE

To identify the body mass index (BMI; in kg/m2) cutoff that predicts the risk for obesity-related metabolic disorders for the Chinese population.

DESIGN

Community-based cross-sectional survey.

SETTING

Rural regions of Jiangxi and Anhui provinces and an urban community of Jing'an District of Shanghai, China.

SUBJECTS

Five hundred and twenty-nine non-pregnant, non-lactating urban and rural adults, aged 20-64 years without diagnosed diabetes.

RESULTS

Subjects were divided into two groups: with or without obesity-related metabolic disorders, which was defined as having at least one of the following: hypertension, insulin resistance, high plasma triacylglycerol, low-density lipoprotein-cholesterol or glucose. Gender-specific multiple logistic regression analysis demonstrated a significant dose-response relationship between BMI and obesity-related metabolic disorders, after adjusting for potential confounders. The lowest BMI interval associated with significant risk for both men and women (odds ratios of 2.67 and 3.46, respectively) was that of 22.5-24.4. Receiver-operating characteristic (ROC) curve analysis indicated that a BMI cutoff of 23 had the best combination of sensitivity and specificity and the shortest distance in the ROC curve, with positive and negative predictive values of 0.6-0.7 in both genders.

CONCLUSIONS

A BMI cutoff of 23 might be appropriate for use in identification of high risk of obesity-related metabolic disorders and serve as a public health action threshold in the Chinese population.

SPONSORSHIP

Center of a Livable Future, John Hopkins Bloomberg School of Public Health.

High Diversity of the Chicken Growth Hormone Gene and Effects on Growth and Carcass Traits

The chicken growth hormone (cGH) gene plays a crucial role in controlling growth and metabolism, leading to potential correlations between cGH polymorphisms and economic traits. In this study, DNA from four divergent chicken breeds were screened for single nucleotide polymorphisms (SNPs) in the cGH gene using denaturing high-performance liquid chromatography and sequencing. A total of 46 SNPs were identified, of which 4 were in the 5' untranslated region, 1 in the 3' untranslated region, 5 in exons (two of which are nonsynonymous), with the remaining 36 in introns. The nucleotide diversity in the cGH gene ( theta = 2.7 x 10(-3)) was higher than that reported for other chicken genes, even within the same breeds. The associations of five of these SNPs and their haplotypes with chicken growth and carcass traits were determined using polymerase chain reaction-restriction fragment length polymorphism analysis in a F2 resource population cross of two of the four chicken breeds (White Recessive Rock and Xinghua). This analysis shows that, among other correlations, G+1705A was significantly associated with body weight at all ages measured, shank length at three of four ages measured, and average daily gain within weeks 0 to 4. Thus, this cGH polymorphism, or another polymorphism that is in linkage disequilibrium with G+1705A, appears to correspond to a significant growth-related quantitative trait locus difference between the two breeds used to construct the resource population.

Antineutrophil cytoplasmic antibodies (ANCA) in Chinese patients with anti-GBM crescentic glomerulonephritis

OBJECTIVE

To study the prevalence of ANCA and their target antigen in Chinese patients with anti-GBM crescentic glomerulonephritis (CGN), and to evaluate the possible role of ANCA in Chinese anti-GBM CGN patients with coexisting serum ANCA by studying clinicopathologic features of this disease.

MATERIAL AND METHODS

Twenty-three sera were collected from 23 renal biopsy-proven anti-GBM CGN patients. According to the standardized procedures, all of the sera were determined by both, indirect immunofluorescence (IIF) ANCA, and enzyme-linked immunosorbent assay (ELISA) MPO-ANCA, PR3-ANCA and BPI-ANCA. The patients were divided into two groups according to serum ANCA positivity (Group A) or negativity (Group B). Thirty-three ANCA-associated pauci-immune CGN patients were regarded as control group (Group C). Their clinicopathologic features were compared to reveal whether ANCA correlated with disease activity.

RESULTS

There were 11 (47.8%) cases with positive serum ANCA in 23 anti-GBM glomerulonephritis patients. There were 4/11 MPO-ANCA (one with positive PR3-ANCA and C-ANCA, three with negative IIF-ANCA), 1/11 PR3-ANCA (with positive MPO-ANCA and C-ANCA), 3/11 P-ANCA (with negative ELISA-ANCA) and 5/11 C-ANCA (one with positive PR3-ANCA and MPO-ANCA, and the other four with negative ELISA-ANCA). No BPI-ANCA was detected. No different clinicopathologic features were found between Groups A and B. Both were different from Group C in age, sex ratio, frequence of anuria and ESRD, variety of crescents, glomerular sclerosis, vessel lesion and prognosis.

CONCLUSION

Our data demonstrate that ANCA in Chinese patients with anti-GBM CGN is not rare. The major target antigen of ANCA is MPO. ANCA seems not to be correlated with disease activity.

Sequence variation and gene duplication at MHC DQB loci of baiji (Lipotes vexillifer), a Chinese river dolphin

The major histocompatibility complex (MHC) is a fundamental part of the vertebrate immune system, and the high variability in many MHC genes is thought to play an important role in the recognition of parasites. Baiji (Lipotes vexillifer) is one of the most endangered species in the world. Its wild population has declined to fewer than 100 individuals and has a very high risk of becoming extinct in the near future. In this study we present a first step in the molecular characterization of a DQB-like locus of baiji by nucleotide sequence analysis of the polymorphic exon 2 segments. In the examined 172 bp sequences from a group of 18 incidentally captured or stranded individuals, 48 variable sites were determined and 43 alleles were identified, many of which were represented by only one clone. Three to seven alleles were found in each individual, suggesting gene duplications. No deletion, insertion, or exceptional stop codon was detected, suggesting these alleles function in vivo. Phylogenetic reconstruction using neighbor joining grouped the 43 alleles into two distinct lineages, differing by seven nucleotides and four amino acids. Substitutions of amino acids tend to be clustered around sites postulated to be responsible for selective peptide recognition. In the peptide-binding region (PBR) of the DQB locus, the average number of nonsynonymous substitutions per site is greater than that of synonymous substitutions per site (0.1962 versus 0.0256, respectively). Nucleotide and amino acid sequences both showed a relatively high level of similarity (nucleotides 90.6%; amino acids 80.6%) to those of beluga whale (Delphinapterus leucas) and narwhal (Monodon monoceros). The high level of baiji MHC polymorphism revealed in the present study has not been reported in other cetaceans and could be a consequence of the small baiji population adapting to freshwater with a relatively high level of pathogens.

Variation in nutrient intakes among women in Shanghai, China

BACKGROUND

In 1997, we launched a large population-based cohort study, the Shanghai Women Health Study (SWHS), to investigate diet in relation to cancer risk among 74 943 Chinese women. Simultaneously, a dietary calibration study was conducted among 200 SWHS participants with biweekly 24-h dietary recall (24HDR) over a 1-y period in order to evaluate the validity and reliability of the SWHS food frequency questionnaire (FFQ).

OBJECTIVE

The objectives of the current study were to evaluate the nature and magnitude of variances for intake of 26 nutrients among SWHS participants, and to estimate the number of 24HDR needed for estimate intake of the 26 nutrients examined in the study population.

DESIGN

In all, 1-y biweekly 24HDR collected from 200 healthy, free-living women aged between 40 and 70 y, who participated in the SWHS dietary calibration study, was analyzed by mixed effects model and ratios of within-individual and between-individual dietary intake variances (sigma(w)(2)/sigma(b)(2)) were estimated.

RESULTS

In agreement with reports from studies conducted in the US, we found that within-individual variances were larger than between-individual variances in dietary intake of most nutrients. The sum of all other variation (eg, weekday and weekend, seasonal, interviewer) accounted for less than 5% of total variation. Ratios of within- to between-individual variances (for log transformed data) ranged from 1.05 (carbohydrate) to 2.79 (fat) for macronutrient intake, 1.74 (niacin) to 8.48 (delta-tocopherol) for vitamin intake, and 1.35 (phosphorus) to 5.59 (sodium) for mineral intake.

CONCLUSIONS

The results of this study suggest that within- and between-individual differences in nutrient intake are the major sources of variation in this population of adult Chinese women. Cultural practices as well as seasonal supply and consumption patterns of vegetable intake are likely the major contributors to the variation. Implications of these results are discussed.

Clinical and cytogenetic features of 508 Chinese patients with myelodysplastic syndrome and comparison with those in Western countries

Myelodysplastic syndrome (MDS) is a clonal hematopoietic stem cell disorder characterized by ineffective hematopoiesis and leukemia progression. Racial differences may exist on clinical pictures and the molecular events leading to MDS, which are heterogeneous. To better define the clinical and cytogenetic features in Chinese patients, a retrospective multicentric study was performed in 508 MDS cases. Compared with Western countries, Chinese patients showed younger age (median: 49 vs 65-73 years), lower percentages of RARS (2.8 vs 6.6-15.3%), and CMML (5.2 vs 11.7-30.6%). Cytogenetically, among 367 cases with evaluable data, abnormal karyotypes were found in 136 cases, including 56 numerical and 80 structural changes. Incidences of single chromosome 5 and 7 abnormalities were lower than those in Western countries (2.2 vs 17.8-42.5%). However, complex cytogenetic aberrations and chromosome translocations were frequently observed and related to poor prognosis. Both multiple chromosome deletions and translocations were detected in advanced subtypes (RAEB and RAEB-T). Analysis of 200 cases revealed a higher incidence of hepatitis-B-virus infection than that in non-MDS population (21.00 vs 9.75%). This study further confirmed: (1) different genetic/environmental backgrounds between Asian and Western MDS populations; (2) a strong predictive value of cytogenetic abnormalities on disease outcome and involvement of genomic instability in leukemia clone development.

Potentiation and cellular phenotypes of the insecticidal Toxin complexes of Photorhabdus bacteria

The toxin complex (tc) genes of bacteria comprise a large and growing family whose mode of action remains obscure. In the insect pathogen Photorhabdus, tc genes encode high molecular weight insecticidal toxins with oral activity against caterpillar pests. One protein, TcdA, has recently been expressed in transgenic plants and shown to confer insect resistance. These toxins therefore represent alternatives to toxins from Bacillus thuringiensis (Bt) for deployment in transgenic crops. Levels of TcdA expression in transgenic plants were, however, low and the full toxicity associated with the native toxin was not reconstituted. Here we show that increased activity of the toxin TcdA1 requires potentiation by either of two pairs of gene products, TcdB1 and TccC1 or TcdB2 and TccC3. Moreover, these same pairs of proteins can also cross-potentiate a second toxin, TcaA1B1. To elucidate the likely functional domains present in these large proteins, we expressed fragments of each 'toxin' or 'potentiator' gene within mammalian cells. Several domains produced abnormal cellular morphologies leading to cell death, while others showed specific phenotypes such as nuclear translocation. Our results prove that the Tc toxins are complex proteins with multiple functional domains. They also show that both toxin genes and their potentiator pairs will need to be expressed to reconstitute full activity in insect-resistant transgenic plants. Moreover, they suggest that the same potentiator pair will be able to cross-potentiate more than one toxin in a single plant.

The role of B7-2 (CD86) in tumour immunity

Tumour cells engineered to express co-stimulatory molecules on their surface provide researchers with powerful new tools to manipulate antitumour responses. It has been demonstrated that B7-1+ and B7-2+ tumour cells can elicit effective responses against their wild-type counterparts. This response is primarily mediated by CD8+ cytolytic T-lymphocytes. The co-stimulatory ability of B7-2+ tumour cells is comparable to that of B7-1+ tumour cells, though with some exceptions. However, on host antigen-presenting cells (APC), B7-2 plays a dominant role in inducing T-cell-mediated immune responses. Up-regulation of B7-2 on host APC may, therefore, present an effective means of generating potent antitumour immunity.

Genomic organisation of the chicken ghrelin gene and its single nucleotide polymorphisms detected by denaturing high-performance liquid chromatography

(1) Ghrelin is a novel endogenous ligand for the growth hormone secretagogue receptor (GHS-R) and is expressed primarily in the stomach and hypothalamus with the probable function of stimulating GH secretion and food intake both in mammals and poultry. The complete sequences of ghrelin gene have been reported in humans and mice; however, that of chickens remains unclear. (2) Here, we report the complete sequence of chicken ghrelin gene (submitted to Genbank; accession number AY303688), which consists of 5 exons and 4 introns. As in mice, the first exon of chicken ghrelin gene does not encode any amino acid. (3) Scanning point mutations with denaturing high-performance liquid chromatography (DHPLC) using WAVE DNA Fragment Analysis Systems and confirmed with direct sequencing for polymerase chain reaction (PCR) products, we analysed the single nucleotide polymorphisms (SNPs) in the entire gene of chicken ghrelin. (4) Results showed that there were 19 SNPs in chicken ghrelin gene, and most of these SNPs were scattered in the 4 introns. In these SNPs, one mutation in exon 5 (A2355G) led to the change of amino acid from glutamine to arginine (Gln 113 Arg): as a result a different ghrelin precursor instead of a mature peptide was produced. In addition, one SNP in 5'UTR (C223G) determined the presence or absence of a potential binding site of transcription factor serum response factor (SRF), which might affect the expression of chicken ghrelin gene. Some of the SNPs detected in the present study could be used in quantitative trait loci (QTL) mapping for growth characters in chickens. (5) Because one SNP is located in a polymorphic site of restriction enzyme PagI of intron 4, it was possible to design a PCR-RFLP procedure and analyse the diversity of 10 chicken populations. Results showed the allelic frequencies of C2100T differ among these breeds, however, no significant difference was observed between imported breeds and Chinese native ones, nor between egg layers and meat type chickens. A chi-square test showed that 4 chicken populations of Beijing Fat, Xinghua, Recessive White and Silky followed the Hardy-Weinberg equilibrium.