Disruption of the retinoblastoma pathway by small interfering RNA and ectopic expression of the catalytic subunit of telomerase lead to immortalization of human ovarian surface epithelial cells

The risk of developing ovarian cancer is about 1% over a lifetime, but it is the most deadly gynecologic cancer, in part due to lack of diagnostic markers for early-stage disease and cell model system for studying early neoplastic changes. Most existing immortal human ovarian surface epithelial cells were achieved by using viral protein such as SV40 T/t antigen or E6/E7, which inactivate multiple cellular pathways. In the current study, we used a small interfering RNA (siRNA) against the retinoblastoma gene (pRb) and ectopic expression of human telomerase reverse transcriptase (hTERT) to immortalize the primary ovarian epithelial cell line OSE137 and two additional human ovarian surface epithelial cells. The immortalized OSE137 showed increased telomerase activity, lengthened telomeres, increased G2/M phase, altered cell-cycle regulatory proteins but nontumorigenic. As both Rb and hTERT pathways are commonly altered in human ovarian cancer and these genetic changes are faithfully modeled in these cells without using viral protein, these immortal cells represent an authentic in vitro model system with which to study the initiation and progression of human ovarian cancer.

IFITM1 plays an essential role in the antiproliferative action of interferon-gamma

Interferon-gamma (IFN-gamma) is a pleiotropic cytokine involved in antiproliferative and anti-virus responses, immune surveillance and tumor suppression. These biological responses to IFN-gamma are mainly mediated by the regulation of gene expression. It has been reported that growth-inhibitory role of IFN-gamma is dependent on activation of signal transducers and activators of transcription 1 (STAT1); however, the molecular basis downstream of STAT1 remains unclear. Here, we report that an IFN-gamma-induced gene, interferon-induced transmembrane protein 1 (IFITM1), plays a key role in the antiproliferative action of IFN-gamma. Overexpression of IFITM1 negatively regulated cell growth, whereas suppression of IFITM1 blocked the antiproliferative effect of IFN-gamma, accelerated the cell growth rate and conferred tumorigenicity to a non-malignant hepatocyte in nude mice. Further, IFITM1 could inhibit the activity of extracellular signal-regulated kinase, enhance the transcriptional activity of p53 and stabilize the p53 protein by inhibiting p53 phosphorylation on Thr55. Suppression of p53 reduced the growth-inhibitory capacity of both IFITM1 and IFN-gamma. Therefore, these findings indicated that the antiproliferative action of IFN-gamma requires the induction of IFITM1, and provided a crosstalk between two well-known signaling mediators, STAT1 and p53, both of which play critical roles in tumor suppression.

Retrovirus molecular conjugates: a versatile and efficient gene transfer vector system for primitive human hematopoietic progenitor cells

In principle, transient nongenetic modification of a noninfectious gene transfer virus enabling a one time infection and transduction of human cells could eliminate the risk of formation of replication competent virus. Formation of a molecular conjugate vector by conjugation of noninfective ecotropic murine Moloney leukemia virus to polylysine (eMMLV-PL) enabled high-efficiency transduction of human HPC using in vitro and in vivo assays. Xenotransplanted NOD-SCID mice durably expressed the transgene in human leukocytes and human progenitor cells with eMMLV-PL achieving three-fold increased transduction efficiency when directly compared to optimized amphotropic MMLV (aMMLV) transduction. Both aMMLV and eMMLV assembled conjugate vectors showed similar transduction efficiency indicating predominant polylysine-mediated uptake. Integration of retroviral sequences was determined from individual human HPC recovered from eMMLV-PL-xenotransplanted animals. This simple and versatile concept of conjugate gene transfer vectors has the potential to enhance transduction efficiency as well as to improve certain safety aspects of human gene therapy. Moreover, because it permits effective cellular internalization of particles, this concept of molecular conjugates can be used as research tool to investigate the interactions of otherwise noninfectious viruses or modified viral particles at the genomic level.

Nature of signals that initiate the immune response during Wallerian degeneration of peripheral nerves

Monocyte chemoattractant protein-1 is produced by Schwann cells during Wallerian degeneration of a peripheral nerve and contributes to a selective accumulation of macrophages in the degenerating segment. An in vitro preparation has been developed to analyze the molecules from axons and non-neuronal cells in nerves that stimulate an increased production of monocyte chemoattractant protein-1 mRNA by Schwann cells. For this purpose, Schwann cells obtained from neonatal rats were maintained in culture, exposed to putative molecular stimuli and analyzed for their content of monocyte chemoattractant protein-1 mRNA. Under basal conditions, the concentration of monocyte chemoattractant protein-1 in Schwann cells was low. Freeze-killed fragments or homogenates of nerve (or brain) but not viable nerve or freeze-killed muscle were effective in inducing monocyte chemoattractant protein-1 mRNA. The inductive activity was abolished by heating. Results of dialysis of supernatants of nerve homogenates indicate that a protein or proteins of 1-10 kDa were capable of stimulating synthesis of monocyte chemoattractant protein-1 by Schwann cells. Also, the activity in nerve homogenates was partially inhibited by antibodies to Toll-like receptor-4. The observations suggest that a non-secreted protein is released from disintegrating axons to initiate the innate immune response that characterizes Wallerian degeneration.

Cerium and boron chemistry in doped borosilicate glasses examined by EELS

Spatially resolved measurements of boron coordination and cerium valency in a doped borosilicate glass with crystalline nano-precipitates are described. The fine structure of the boron K-edge and the white-line ratio of the cerium M-edge doublet were evaluated from EELS line scans. Due to high beam sensitivity it was found that reliable boron-coordination measurements in some of the glasses studied required extrapolation of results acquired after different periods of irradiation back to a zero-irradiation. However, borosilicates that contained heavy alkali atoms were found to suffer very little structural change. The Ce valency of a 4% (molar) doped alkali-borosilicate glass was found to be mixed +III/+IV in the glass matrix and purely +IV (indicative of CeO2) in the precipitates. A significant dependency of the valence results on the data processing method was found and explained.

Histone deacetylase inhibitors induce the degradation of the t(8;21) fusion oncoprotein

The t(8;21) chromosomal translocation that generates the fusion oncoprotein RUNX1-ETO predominates in leukemia patients of the French-American-British (FAB) class M2 subtype. The oncoprotein has the capacity to promote expansion of hematopoietic stem/progenitor cells and induces leukemia in association with other genetic alterations. Here, we show that RUNX1-ETO undergoes degradation in response to treatment with histone deacetylase inhibitors, one of which, depsipeptide (DEP), is currently undergoing phase II clinical testing in a variety of malignancies. These compounds induce turnover of RUNX1-ETO without affecting the stability of RUNX1-ETO partner proteins. In addition, RUNX1-ETO physically interacts with heat shock protein 90 (HSP90). DEP treatment interrupts the association of RUNX1-ETO with HSP90 and induces proteasomal degradation of RUNX1-ETO. DEP and the HSP90 antagonist 17-allylamino-geldanamycin (17-AAG) both triggered RUNX1-ETO degradation, but without any additive or cooperative effects. These findings may stimulate the development of more rational and effective approaches for treating t(8;21) patients using histone deacetylase inhibitors or HSP90 inhibitors.

Outcomes and toxicities among octogenarians and nonagenarians with colorectal cancer (crc) treated with chemotherapy or concurrent chemoradiation - a single institution study

13514

Background: Chemotherapy is associated with an improved overall survival with acceptable toxicities in patients ≥ 70 years. However, little to no data exists regarding feasibility and tolerability of chemotherapy and/or radiation in CRC patients ≥ 80 years. The purpose of this study was to identify the trends of increased toxicity in this subgroup of patients. Methods: A retrospective study on patients ≥ 80 yrs treated for CRC with either chemotherapy alone or chemoradiation during the period of 1996- 2005 at Roswell Park Cancer Institute was conducted. Survival analysis was performed using the Kaplan-Meier method. Results: 29 patients were identified. 8 patients were diagnosed as having rectal cancer and received combined chemoradiation. 21 patients had colon cancer and received chemotherapy alone either in the adjuvant or metastatic setting. The median age was 82 years (range: 80–93). The median survival for all stages receiving chemo and/or radiation therapy was 37 months (95% CI: 27–53). The median survival for patients with stage IV disease was 6 months (95% CI: 5–33). Grade III/IV GI toxicities were seen in 59% (95% CI: 37–72%) of patients. Grade III/IV hematologic toxicities were seen in 17% (95% CI: 8–37%) of patients. Empiric chemotherapy dose reductions were implemented, starting the first cycle, in 90% (95% CI: 72–96%)of patients. Therapy had to be withheld in 34% (95% CI: 19–52%) of patients by more than 1 week due to toxicities in the first 2 months of treatment. Conclusions: Our study, demonstrates a higher rate of toxicities than previously reported for patients ≥ 70 years. This has occurred despite an initial dose-reduction in the majority of the treated population (90%). Octogenarian and nonagenarian CRC patients experienced a higher rate of GI toxicities during treatment, some of which were life threatening. This data supports the urgent need to conduct prospective studies to identify treatment recommendations for patients ≥ 80. Data from larger elderly phase II studies with median ages < 80 should not be extrapolated to octogenarians and nonagenarians.

No significant financial relationships to disclose.

Serial hypoxia imaging with 99mTc-HL91 SPECT to predict radiotherapy response in non-small cell lung cancer

7143

Background: To evaluate the relationship between 99mTc-HL91 (99mTc labeled 4,9-diaza-3,3,10,10-tetramethyldodecan-2,11-dione dioxime) SPECT (single photon emission computed tomography) hypoxia imaging and the radiotherapy outcome and also to assess changes in tumor oxygenation during the course of treatment. Methods: 32 patients with pathologically proven non-small cell lung cancer received three-dimensional conformal radiotherapy were enrolled into the study. All patients were performed 99mTc-HL91 SPECT scanning at one or two days before radiotherapy. 18 patients were also performed during radiotherapy (30–40 Gy) and one or two days after radiotherapy. Anterior, posterior and lateral planar images were collected at 2 hours, 4 hours and 6 hours respectively after intravenous injection approximately 740MBq 99mTc-HL91. Regions of interest (ROIs) were drawn in the tumor and contralateral normal lung tissue and the radioactivity ratios of tumor to normal tissue (T/N) were calculated. Results: The relationship between T/N ratios at 4h images after injection which was shown as the best of three acquired images before radiotherapy and the response and over survival to radiotherapy were analyzed for all 32 patients. The results of 99mTc-HL91 imaging of 32 patients correlate well with radiotherapy response (P = 0.049) and also patient survival (P = 0.043). The average T/N value of 18 patients who receiving serial scanning was 1.57 ± 0.18, 1.44 ± 0.19 and 1.30 ± 0.14 respectively. There was significant statistic difference between these three groups (P = 0.000). Conclusions: HL91 SPECT imaging identified the hypoxia status and changes during radiotherapy in lung cancer. It was confirmed that hypoxia imaging with HL91 SPECT before treatment may predict radiotherapy response and patient survival. The relationship between T/N ratio and radiotherapy outcome in NSCLC

[Table: see text]

No significant financial relationships to disclose.

Building capacity for tobacco control research and policy

The Fogarty International Center (FIC) initiative, "International Tobacco and Health Research Capacity Building Program" represents an important step in US government funding for global tobacco control. Low- and middle-income countries of the world face a rising threat to public health from the rapidly escalating epidemic of tobacco use. Many are now parties to the Framework Convention on Tobacco Control (FCTC) and capacity development to meet FCTC provisions. One initial grant provided through the FIC was to the Institute for Global Tobacco Control (IGTC) at the Johns Hopkins Bloomberg School of Public Health (JHSPH) to support capacity building and research programmes in China, Brazil, and Mexico. The initiative's capacity building effort focused on: (1) building the evidence base for tobacco control, (2) expanding the infrastructure of each country to deliver tobacco control, and (3) developing the next generation of leaders as well as encouraging networking throughout the country and with neighbouring countries. This paper describes the approach taken and the research foci, as well some of the main outcomes and some identified challenges posed by the effort. Individual research papers are in progress to provide more in-depth reporting of study results.

HLA-A, -B, and -DRB1 polymorphism defined by sequence-based typing of the Han population in Northern China

DNA typing for human leukocyte antigen (HLA)-A, -B and -DRB1 was performed using polymerase chain reaction-sequence-based typing method on 618 randomly selected healthy individuals of the Han population in Northern China. Allele frequencies and haplotypes were statistically analyzed. A total of 84 HLA-A alleles, 143 B alleles, and 122 DRB1 alleles were detected, and 853 A-B-DRB1 haplotypes, 473 A-B haplotypes, and 551 B-DRB1 haplotypes were statistically inferred. Statistical analysis of three-locus haplotypes showed that A*0207-B*4601-DRB1*0901 (3.06%) was the most predominant. Gene frequencies and haplotypic associations within HLA-A, -B, and -DRB1 loci were determined at a high-resolution (four digit) allelic level and should provide useful information in anthropology, bone marrow donor registry, legal medicine, and disease association studies.

MELPREDICT: a logistic regression model to estimate CDKN2A carrier probability

BACKGROUND

Heritable alterations in CDKN2A account for a subset of familial melanoma cases although no robust method exists to identify those at risk of being a mutation carrier.

METHODS

We set out to construct a model for estimating CDKN2A mutation carrier probability using a cohort of 116 consecutive familial cutaneous melanoma patients evaluated at Massachusetts General Hospital Pigmented Lesion Center between April 2001 and September 2004. Germline CDKN2A and CDK4 status on the familial melanoma cases and clinical features associated with mutational status were then used to build a multiple logistic regression model to predict carrier probability and performance of model on external validation.

RESULTS

From the 116 kindreds prone to melanoma in the Boston area, 13 CDKN2A mutation carriers were identified and 12 were subsequently used in the modeling. Proband age at diagnosis, number of proband primaries, and number of additional family primaries were most closely associated with germline mutations. The estimated probability of the proband being a mutation carrier based on the logistic regression model (MELPREDICT) is given by e(L)/(1 + e(L) where L = 1.99+[0.92x(no. of proband primaries)]+[0.74x(no. of additional family primaries)]-[2.11xln(age)]. The mean estimated probabilities for subjects in the Boston dataset were 55.4% and 5.1% for the mutation carriers and non-carriers respectively. In a receiver operator characteristic analysis, the area under the curve was 0.881 (95% confidence interval 0.739 to 1.000) for the Boston model set (n = 116) and 0.803 (0.729 to 0.877) for an external Toronto hereditary melanoma cohort (n = 143).

CONCLUSIONS

These results represent the first-iteration logistic regression model to approximate CDKN2A carrier probability. Validation of this model with an external dataset revealed relatively robust performance.

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.