Ozone sensitivity to its precursor emissions in northeastern Mexico for a summer air pollution episode

A summer episode was modeled to address the expected response of ambient air O3 to hypothetical emission control scenarios in northeastern Mexico, and in particular in the Monterrey Metropolitan Area (MMA). This region is of interest because the MMA holds one of the worst air quality problems in the country and levels of air pollutants in the rest of northeastern Mexico are starting to be a concern. The MM5-SMOKE-CMAQ platform was used to conduct the numerical experiments. Twenty-four control scenarios were evaluated, combining the level of emission controls of O3 precursors (NO(x) and volatile organic compounds [VOCs]) from 0% to 50%. For the MMA, VOC-only controls result in the best option to reduce O3 concentrations, though the benefit is limited to the urban core. This same strategy results in negligible benefits for the rest of northeastern Mexico. NO(x) controls result in an increase in O3 concentration within the MMA of up to 20 ppbv and a decrease at downwind locations of up to 11 ppbv, with respect to the base-case scenario. Indicator ratios were also used to probe for NO(x)-sensitive and VOC-sensitive areas. Locations with an important influence of NO(x) point sources (i.e., Monclova and Nava/Acuña) are quite sensitive to changes in NO(x) emissions. Border cities in the Rio Bravo/Grande Valley tend to be marginally NO(x)-sensitive. Overall, the MMA seems to be dominated by a VOC-sensitive regime, while the rest of the region would tend to have a NO(x)-sensitive response. The results obtained serve to expand the current knowledge on the chemical regimes that dominate this region (VOC- or NO(x)-sensitive), and thus could help guide public policies related to emission regional control strategies.

A novel noninvasive method for evaluating experimental lung metastasis in mice

Metastasis remains the most significant problem in the field of cancer. The biologic complexity that characterizes metastasis requires relevant in vivo models. When using murine models for pulmonary metastasis, longitudinal studies are valuable for following the progression of metastatic burden. Currently, the progression of pulmonary metastatic burden in experimental mice over time is monitored through advanced imaging approaches or the clinical assessment of morbidity. Because clinical signs of morbidity are often vague and unpredictable, an inexpensive and reproducible method to detect advanced metastatic burden-before the development of mortality-is needed. We have developed a noninvasive technique for assessing pulmonary metastatic burden in laboratory mice. The pulmonary assessment of advanced metastasis (PAAM) test is performed by restraining an awake mouse and gently applying pressure with the index finger under the xiphoid process. This pressure reduces the diaphragmatic component to respiration. Mice with advanced lung metastases show transient signs of respiratory distress within 3 s of the application of this pressure. Using PAAM in 4 distinct models (including sarcoma and mammary carcinoma histologies) of experimental (tail vein) pulmonary metastasis (n = 114 mice), among 3 independent evaluators yielded 94% positive and negative predictive values, which were validated by histologic assessment of postmortem lung tissue. PAAM is a simple, reproducible, and efficient method to assist in the detection of advanced pulmonary metastasis in mice and contributes to their humane care during longitudinal studies.

3,5-T2 is an alternative ligand for the thyroid hormone receptor β1

Several liganded nuclear receptors have alternative ligands acting in a tissue-specific fashion and playing important biological roles. We present evidence that 3,5-diiodothyronine (T(2)), a naturally occurring iodothyronine that results from T(3) outer-ring deiodination, is an alternative ligand for thyroid hormone receptor β1 (TRβ1). In tilapia, 2 TRβ isoforms differing by 9 amino acids in the ligand-binding domain were cloned. Binding and transactivation studies showed that T(2) activates the human and the long tilapia TRβ1 isoform, but not the short one. A chimeric human TRβ1 (hTRβ1) that contained the 9-amino-acid insert showed no response to T(2), suggesting that the conformation of the hTRβ1 naturally allows T(2) binding and that other regions of the receptor are implicated in TR activation by T(2). Indeed, further analysis showed that the N terminus is essential for T(2)-mediated transactivation but not for that by T(3) in the long and hTRβ1, suggesting a functional interaction between the N-terminal domain and the insertion in the ligand-binding domain. To establish the functional relevance of T(2)-mediated TRβ1 binding and activation, mRNA expression and its regulation by T(2) and T(3) was evaluated for both isoforms. Our data show that long TRβ1expression is 10(6)-fold higher than that of the short isoform, and T(3) and T(2) differentially regulate the expression of these 2 TRβ1 isoforms in vivo. Taken together, our results prompted a reevaluation of the role and mechanism of action of thyroid hormone metabolites previously believed to be inactive. More generally, we propose that classical liganded receptors are only partially locked to very specific ligands and that alternative ligands may play a role in the tissue-specific action of receptors.

Role of IGF-1R inhibition on an Src-family kinase bypass resistance pathway: A rational basis for cotargeting IGF-1R and Src kinase in pediatric sarcomas?

10025

Background: Dysregulation of IGF signaling plays a fundamental role in oncogenesis in pediatric sarcomas. We recently completed a Phase II study targeting the IGFI receptor signaling pathway in refractory Ewing’s and other sarcomas. We demonstrated an objective response rate of 16 percent, but most responses were transient lasting less than 18 weeks. The majority of patients, even those with initial responses, do not have long term benefit from IGFIR blockade, indicating the presence of an innately resistant tumor mass or the recruitment of compensatory pathways allowing for continued growth. To improve on these responses, we have been probing these tumors to identify other critical pathways that might allow combined targeting approaches. Methods: Multiple RMS and ES cell lines were treated with IGF1R kinase inhibitors and assayed for up-regulation of various signaling pathways. Combination treatment with IGF1R inhibitors and inhibitors of additional signaling pathways were then tested in vitro and in vivo using standard techniques. For in vivo xenograft studies, treatments began 11 days following orthotopic injection of tumor cells. Results: We have identified repid up-regulation of Src family kinase (SFK) signaling within 4 hours of IGF1R blockade in both RMS and ES cell lines. Of note, combined treatment with IGF1R Ab plus IGF1R kinase inhibitors most potently upregulated SFK signaling. Based on these findings, we tested combined IGF1R blockade with SFK inhibition using the commercially available drug, dasatinib. We show that dual blockade of IGF1R and SFK pathways were synergistic in vitro. Furthermore, in xenograft models of RMS, the combination IGF1R and SFK inhibition led to long-term disease free status for at least 90 days in some mice, never seen in our hands previously using these models. Conclusions: This work identified that IGF-1R inhibition induced activation of Src kinase that may act as a by-pass pathway. Synergistic activity of IGF-1R and SFK kinase inhibitors was observed in vitro and in vivo. Dual IGFI and SFK kinase inhibition may lead to improved therapeutic outcomes.

The natural history of Parkinson's disease in the province of Segovia: mortality in a longitudinal study (20-year follow-up)

OBJECTIVE

We determined mortality rates and predictors of survival in 273 patients with Parkinson's disease based on a 20-year follow-up longitudinal study.

MATERIAL AND METHODS

We examined 273 patients with Parkinson's disease during a 20-year follow-up, recruited between 1978 and 1998. All patients were regularly followed at the Department of Neurology until December 31, 1998, or death.

RESULTS

By then, 69 patients had died, crude mortality was rate 4.43, and standardized mortality ratio for the total patient group was 1.39 (95% CI, 1.10-1.50). As Parkinson's disease is a chronic progressive disorder in adult life, disease-related mortality would be expected to increase in later stages after 15 or 20 years. Mean age at death in our cohort was 78.27 (95% CI, 76.90-79.20). Median time of death was 11 years (95% CI, 9.50-12.49). Independent predictors of mortality during the follow-up were age at onset (hazard ratio, 1.05; 95% CI, 1.01-1.09; P = 0.01), clinical form - akinesia and rigidity (hazard ratio, 2.20; 95% CI, 1.06-4.88; P = 0.03) - and treatment with dopaminergic agonist (hazard ratio, 0.49; 95% CI, 0.23-1.03; P = 0.06). Cardiovascular disease was the most frequent cause of death in 42%.

CONCLUSIONS

This study suggests a link between mortality with age of onset and treatment without dopamine agonists as initial treatment. So, there is an association between decreased mortality and tremor as initial clinical forms at onset.

Abstract LB-284: Bone marrow-derived progenitor cells develop into myeloid-derived suppressor cells at metastatic sites

The ability of tumor cells to metastasize to distant tissues is the most lethal aspect of cancer. Prior to detectable metastasis tumors elicit distant changes within the bone marrow and future sites of metastasis, including formation of the pre-metastatic niche. We have found that prior to detectable spontaneous metastasis, a primary tumor causes enhanced production and mobilization of progenitor cells from the bone marrow into the blood. We find in cancer patients that increased circulating progenitors are associated with metastatic disease progression. By utilizing bone marrow transplant models and a novel ex vivo lung culture, we demonstrate that bone marrow-derived progenitor cells accumulate at the primary tumor as well as metastatic lesions. As our cancer models approach detectable spontaneous metastases, we observe a loss of progenitor cells in pre-metastatic sites and an increase in myeloid-derived suppressor cells (MDSCs). We further traced adoptively transferred bone marrow-derived progenitors in tumor-bearing mice and demonstrate that these cells contribute to the MDSC population. Together, these data suggest that circulating progenitor cells provide a prognostic tool to predict metastatic dissemination. Furthermore, these cells likely contribute to metastatic progression by developing into MDSCs within the primary tumor and at metastatic sites.

Citation Format: Amber Giles, Yorleny Vicioso, Christianne Persenaire, Miki Kasai, Steven Highfill, Arnulfo Mendoza, Rosandra Kaplan. Bone marrow-derived progenitor cells develop into myeloid-derived suppressor cells at metastatic sites. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr LB-284. doi:10.1158/1538-7445.AM2013-LB-284

Prediction of coarctation of the aorta in the second half of pregnancy

OBJECTIVE

To determine which combination of cardiac parameters provides the best prediction of postnatal coarctation of the aorta (CoAo) in fetuses with cardiac asymmetry.

METHODS

We selected all cases of disproportion of the ventricles and great vessels prenatally diagnosed between 2003 and 2010 at the Hospital Universitario '12 de Octubre', Madrid, Spain. Only appropriate-for-gestational age liveborn fetuses with isolated cardiac asymmetry and with complete postnatal follow-up were included in the study. Eighty-five cases were retrieved and analyzed. Logistic regression analysis was used to select the best predictors of CoAo. Optimal cut-offs for these parameters were identified and the corresponding likelihood ratios used to calculate the post-test probability of CoAo in each fetus.

RESULTS

CoAo was confirmed in 41/85 neonates (48%). The parameters selected by logistic regression and their cut-off values were: gestational age at diagnosis ≤ 28 weeks, Z-score of diameter of the ascending aorta ≤ -1.5, pulmonary valve/aortic valve diameters ratio ≥ 1.6 and Z-score of the aortic isthmus diameter in the three vessels and trachea view ≤ -2. We divided the study group into two subgroups: Group A, in whom the diagnosis was made at ≤ 28 weeks' gestation (80% CoAo (32/40)); and Group B, in whom the diagnosis was made at > 28 weeks (20% CoAo (9/45)). The mean post-test probabilities of CoAo were higher in fetuses with CoAo than in normal fetuses in both subgroups (Group A, 82 vs 55%; P = 0.002 and Group B, 51 vs 20%; P < 0.001). In addition, a rate of growth of the aortic valve of ≤ 0.24 mm/week provided 80% sensitivity and 100% specificity for predicting CoAo in Group A.

CONCLUSIONS

We have derived a multiparametric scoring system, combining size-based cardiac parameters and gestational age at diagnosis, which may improve the accuracy of fetal echocardiography for the stratification of the risk of CoAo. The objectivity and simplicity of its components may allow its implementation in fetal cardiology units.

Short synthesis and antimalarial activity of fagaronine

Herein, we report a new synthesis of fagaronine 1, inspired by the synthesis reported by Luo for nornitidine. The in vitro biological activity of fagaronine against malaria on several chloroquine-sensitive and resistant Plasmodium falciparum strains was confirmed, and the selectivity index compared to mammalian cells was calculated. Fagaronine was found to have very good antimalarial activity in vivo, comparable to the activity of the reference compound chloroquine. Therefore, fagaronine appears to be a good potential lead for the design of new antimalarial molecules.

Abstract 2497: ET-743 interferes with EWS-FLI1 driven WRN expression in Ewing sarcoma cells and sensitizes to topoisomerase I inhibitors

The hallmark of Ewing sarcoma is the EWS-FLI1 transcription factor believed to be responsible for oncogenesis and tumor progression. ET-743 (Trabectedin, Yondelis™) is a natural product recently identified as a particularly active agent for Ewing sarcoma cells in vitro. We have recently demonstrated that ET-743 interferes with the activity of the oncogenic transcription factor EWS-FLI1. In this report, we examine the link between EWS-FLI1 suppression and the DNA damage response. We hypothesize that blocking the EWS-FLI1 associated DNA damage response may confer additional sensitivity to specific cytotoxic agents. DNA repair pathways and EWS-FLI1 targets were evaluated by microarray expression, western blot analysis and siRNA interference. Microarray expression and western blot analysis revealed that ET-743 suppresses WRN and XRCC4 expression, critical proteins in the Non-Homologous End Joining Pathway (NHEJ) repair pathway. Further siRNA data showed that the EWS-FLI1 transcription factor drives the expression of WRN. These results suggest that WRN suppression by ET-743 is occurring through an EWS-FLI1 dependent mechanism. Since the NHEJ pathway is associated with resistance to specific chemotherapeutic agents, several combination therapies were investigated in vitro. ESFT cells show heightened sensitivity to the combination of ET-743 and the topoisomerase I inhibitor, SN-38. This result was unique to topoisomerase I inhibitors and further restricted to ESFT cell lines. Consistent with these results, previous reports have established that WRN deficient cells are hypersensitive to topoisomerase I but not topoisomerase II inhibitors. Additionally, we found that irinotecan augments the ET-743 mediated transcriptional inhibition of EWS-FLI1. Taken together these mechanisms account for the heightened sensitivity of the combination of ET-743 and irinotecan observed both in vitro and in vivo in two different ESFT xenograft models. In summary, by employing a mechanism based approach, we have identified a novel combination therapy of ET-743 and irinotecan. By linking the EWS-FLI1 transcriptional program to the DNA damage response in ESFT cells, we expose an inherent weakness to topoisomerase I inhibitors thus creating a cell type specific sensitivity to the drug. This report provides a novel method of oncogenic transcription factor targeting that involves direct suppression of downstream targets and exploitation of the resulting changes in gene expression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 2497. doi:1538-7445.AM2012-2497

Abstract 1365: The PAMM (pulmonary assessment of metastatic morbidity) diagnostic: A novel non-invasive method for evaluating lung metastasis in murine models

Metastasis continues to be the most significant problem in the field of cancer. The biological complexity that characterizes metastasis requires relevant experimental systems for its study, necessitating the use of animal models. When using murine models for pulmonary metastasis, it is valuable to conduct longitudinal studies during which progression of metastatic burden in the lung occurs. Current methods for evaluating pulmonary metastatic burden in experimental mice are limited to advanced imaging approaches or to the development of morbidity linked to pulmonary metastasis. Unfortunately, clinical signs of morbidity are often vague and unpredictable. A novel, inexpensive, clinical method to detect advanced metastatic burden in mice before the development of significant morbidity or mortality would be beneficial to the study of metastasis in mice. With this goal in mind we have developed a novel, non-invasive technique for assessing pulmonary metastatic burden in laboratory mice. The PAMM (Pulmonary Assessment of Metastatic Morbidity) test is performed by restraining an awake mouse and gently applying pressure with the index finger under the xiphoid process. This pressure reduces the diaphragmatic component to respiration. Mice with advanced lung metastases will show signs of respiratory distress within 3 seconds of applying this pressure. Application of this method in 4 models of pulmonary metastasis (n=27 mice including sarcoma and mammary carcinoma histologies), amongst 3 independent “users,” yielded 100% positive and 100% negative predictive values that were validated by post mortem examination. In summary, the PAMM method is a simple, inexpensive, reproducible and efficient method to assist in the detection of advanced pulmonary metastasis. This method contributes to the humane care of mice included in longitudinal studies of pulmonary metastasis.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1365. doi:1538-7445.AM2012-1365

Dysregulation of ezrin phosphorylation prevents metastasis and alters cellular metabolism in osteosarcoma

Ezrin links the plasma membrane to the actin cytoskeleton where it plays a pivotal role in the metastatic progression of several human cancers; however, the precise mechanistic basis for its role remains unknown. Here, we define transitions between active (phosphorylated open) and inactive (dephosphorylated closed) forms of Ezrin that occur during metastatic progression in osteosarcoma. In our evaluation of these conformations we expressed C-terminal mutant forms of Ezrin that are open (phosphomimetic T567D) or closed (phosphodeficient T567A) and compared their biologic characteristics to full-length wild-type Ezrin in osteosarcoma cells. Unexpectedly, cells expressing open, active Ezrin could form neither primary orthotopic tumors nor lung metastases. In contrast, cells expressing closed, inactive Ezrin were also deficient in metastasis but were unaffected in their capacity for primary tumor growth. By imaging single metastatic cells in the lung, we found that cells expressing either open or closed Ezrin displayed increased levels of apoptosis early after their arrival in the lung. Gene expression analysis suggested dysregulation of genes that are functionally linked to carbohydrate and amino acid metabolism. In particular, cells expressing closed, inactive Ezrin exhibited reduced lactate production and basal or ATP-dependent oxygen consumption. Collectively, our results suggest that dynamic regulation of Ezrin phosphorylation at amino acid T567 that controls structural transitions of this protein plays a pivotal role in tumor progression and metastasis, possibly in part by altering cellular metabolism.

Influence of topographical features on the fluoride corrosion of Ni-Ti orthodontic archwires

Different manufacturing processes of Ni-Ti archwires respond differently to corrosion due to the surface conditions involved. In this study, several topographical features and their influence upon fluoride corrosion were studied. Four topographies (smooth, dimple, scratch, and crack) according to the main surface defect were characterized (n = 40). Static corrosion tests were performed in artificial saliva with fluorated prophylactic gel (12500 ppm) for 28 days. The surface was characterized by SEM and laser confocal microscopy. Standard electrochemical corrosion (open circuit potential, corrosion potential and corrosion current density) was performed. Statistical analysis was carried out using the ANOVA test (α ≤ 0.05). An increase was observed in the surface defects and/or roughness of the cracked and scratched surfaces. These defects produced an important increase in corrosion behavior. The best surfaces for the orthodontic archwires were the smooth and dimpled surfaces, respectively. The increase in defects was independent of roughness. Manufacturing processes that produce surface cracks should be avoided in orthodontic applications.

Abstract A103: ET-743 and irinotecan cooperate to inhibit the EWS/FLI1 transcription factor and the associated DNA damage response

Background: ET-743 (Trabectedin, Yondelis™) is a natural product recently identified as a particularly active agent for Ewing's sarcoma cells in vitro. ET-743 interferes with the activity of the oncogenic transcription factor EWS/FLI1 in Ewing's sarcoma cells. In addition ET-743 induces DNA damage and poisons DNA damage repair pathways. In this report, we hypothesized that the EWS-FLI1 transcriptional program may mediate aspects of the DNA damage response. Therefore, interference with EWS/FLI1 activity by ET-743 may confer additional sensitivity to specific cytotoxic agents.

Methods: DNA repair pathways and EWS/FLI1 targets were evaluated by microarray expression, western blot analysis and siRNA interference. To optimize the activity of ET-743 in Ewing's sarcoma several combination therapies were investigated in vitro. The combination of ET-743 and Irinotecan was further evaluated in vivo with two ESFT xenograft models.

Results: ESFT cells displayed increased sensitivity to the combination of ET-743 and the topoisomerase I inhibitor, SN-38. This result was unique to topoisomerase I inhibitors and further restricted to ESFT cell lines. Preliminary xenograft results suggest the combination is also effective in vivo. This sensitivity can be accounted for by both the impaired DNA damage response and greater transcriptional inhibition of EWS/FLI1. Previous reports have established that cells deficient in WRN, a critical protein in the NHEJ DNA repair pathway, are hypersensitive to topoisomerase I inhibitors. Microarray expression and western blot analysis revealed that ET-743 suppresses WRN expression. Further siRNA data showed that the EWS/FLI1 transcription factor drives the expression of WRN. These results suggest that WRN suppression by ET-743 is occurring through an EWS/FLI1 dependent mechanism. Additionally Irinotecan augments the transcriptional inhibition of EWS/FLI1, as evident by suppression of downstream targets.

Conclusion: We have proposed a mechanism for the clinically relevant combination treatment of ET-743 and Irinotecan by interfering with the DNA damage response and augmenting the transcriptional interference of EWS/FLI1. By linking the EWS-FLI1 transcriptional program to the DNA damage response in ESFT cells, we expose an inherent weakness to topoisomerase I inhibitors thus creating a cell type specific sensitivity to the drug. In addition, we found Irinotecan cooperates with the ET-743 mediated suppression of EWS/FLI1 targets. These two effects increase the sensitivity of ESFT cells to this drug combination. Finally, the report provides a novel method of oncogenic transcription factor targeting that involves direct suppression of downstream targets and exploitation of the resulting changes in gene expression.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference: Molecular Targets and Cancer Therapeutics; 2011 Nov 12-16; San Francisco, CA. Philadelphia (PA): AACR; Mol Cancer Ther 2011;10(11 Suppl):Abstract nr A103.

Tetralogy of Fallot: prediction of outcome in the mid-second trimester of pregnancy

OBJECTIVE

To evaluate the usefulness of fetal echocardiography in the mid-second trimester in predicting postnatal outcome of tetralogy of Fallot (ToF), focusing on the need for early intervention (EI) and surgery type: pulmonary valve-sparing surgery (PVSS) versus placement of transannular patch (TAP).

METHODS

Assessment of cardiac morphological and functional parameters in 23 live-born fetuses with isolated ToF was performed at 19 to 22 and 34 to 38  weeks. Comparisons were made between outcome groups (EI vs non-EI and PVSS vs TAP). EI was considered as requirement either of palliative procedure or corrective surgery before three months.

RESULTS

Overall survival was 96%. EI was required in 32% of cases and TAP in 50%. At 19 to 22  weeks, a pulmonary valve peak systolic velocity (PVPSV) ≥87.5 cm/s predicted EI with 100% sensitivity and 93.3% specificity (p < 0.01). At 34 to 38  weeks, the size of the pulmonary valve, pulmonary valve/aortic valve and main pulmonary artery/ascending aorta were significantly different, but the PVPSV again yielded the best performance: all cases undergoing EI and/or TAP were selected using cut-off of ≥144.5 cm/s.

CONCLUSION

The postnatal outcome of fetuses with ToF may be established using PVPSV from the mid-second trimester. This may be useful in providing the most appropriate perinatal management and accurate parental counselling.

Identification of an inhibitor of the EWS-FLI1 oncogenic transcription factor by high-throughput screening

BACKGROUND

Chromosomal translocations generating oncogenic transcription factors are the hallmark of a variety of tumors, including many sarcomas. Ewing sarcoma family of tumors (ESFTs) are characterized by the t(11;22)(q24;q12) translocation that generates the Ewing sarcoma breakpoint region 1 and Friend leukemia virus integration 1 (EWS-FLI1) fusion transcription factor responsible for the highly malignant phenotype of this tumor. Although continued expression of EWS-FLI1 is believed to be critical for ESFT cell survival, a clinically effective small-molecule inhibitor remains elusive likely because EWS-FLI1 is a transcription factor and therefore widely felt to be "undruggable."

METHODS

We developed a high-throughput screen to evaluate more than 50 000 compounds for inhibition of EWS-FLI1 activity in TC32 ESFT cells. We used a TC32 cell-based luciferase reporter screen using the EWS-FLI1 downstream target NR0B1 promoter and a gene signature secondary screen to sort and prioritize the compounds. We characterized the lead compound, mithramycin, based on its ability to inhibit EWS-FLI1 activity in vitro using microarray expression profiling, quantitative reverse transcription-polymerase chain reaction, and immunoblot analysis, and in vivo using immunohistochemistry. We studied the impact of this inhibition on cell viability in vitro and on tumor growth in ESFT xenograft models in vivo (n = 15-20 mice per group). All statistical tests were two-sided.

RESULTS

Mithramycin inhibited expression of EWS-FLI1 downstream targets at the mRNA and protein levels and decreased the growth of ESFT cells at half maximal inhibitory concentrations between 10 (95% confidence interval [CI] = 8 to 13 nM) and 15 nM (95% CI = 13 to 19 nM). Mithramycin suppressed the growth of two different ESFT xenograft tumors and prolonged the survival of ESFT xenograft-bearing mice by causing a decrease in mean tumor volume. For example, in the TC32 xenograft model, on day 15 of treatment, the mean tumor volume for the mithramycin-treated mice was approximately 3% of the tumor volume observed in the control mice (mithramycin vs control: 69 vs 2388 mm(3), difference = 2319 mm(3), 95% CI = 1766 to 2872 mm(3), P < .001).

CONCLUSION

Mithramycin inhibits EWS-FLI1 activity and demonstrates ESFT antitumor activity both in vitro and in vivo.

Abstract 1446: Dissecting the role of PTEN/Akts in metastatic melanoma

Melanoma is an aggressive human cancer whose incidence is increasing more rapidly than any other cancer in the United States. It is characterized by an extremely high potential to develop metastases and poor response to current therapy. Although the genetic studies indicated that melanoma genesis related with molecular lesions in c-MET, INK4a, Ras/Raf, p53 and PTEN pathways, the molecular mechanism inciting metastatic melanoma are poorly understood. PTEN is a major tumor suppressor in humans. To study the role of PTEN in progression of human melanoma, we first used tissue microarrays to examine PTEN expression in 30 lymph node melanoma metastases, 30 primary melanomas, and 9 normal skin tissues. Our results showed that PTEN loss was significantly correlated with progression to the metastatic state. Moreover, analysis of various human melanoma cell lines demonstrated that PTEN expression was related to metastatic behavior, supporting the notion that PTEN is involved in the metastatic regulation of melanoma. PTEN has phosphatase activity that can act upon both polypeptide and phosphoinositide substrates. The PTEN lipid phosphatase is a ubiquitous regulator of PI3K signaling pathway. The loss of expression or mutational inactivation of PTEN protein enhances the phosphorylation of PKB/AKT and thus influences cell survival signaling. Interestingly, a PTEN mutant, which loses lipid but not protein phosphatase activity, lacks the ability to induce either G1 arrest or apoptosis, but nonetheless retains the ability to inhibit cell spreading and motility, suggesting that PTEN protein phosphatase activity is important for these behaviors. To further dissect the role of this PTEN activity in metastasis, we have established a model system containing exploiting mutant PTEN proteins with various phosphatase activities. We found that wild type PTEN can inhibit cell motility and invasiveness, while PTEN mutants cannot. Notably, wild type PTEN was able to reduce the metastatic potential of melanoma cells, whereas phosphatase deficient PTEN could promote the melanoma cell metastatic behavior. We found that PTEN mediates metastatic activity through the AKT pathway. We further determined that Akt 3 was key mediators of metastatic potential in melanoma cells in vivo. Akt3 could also rescue PTEN-mediated inhibition of metastasis. PTEN loss and Akt3 overexpression functioned synergistically to promote metastasis. Our data demonstrate that metastatic behavior in melanoma cells is dependent on the status of PTEN protein phosphatase activity and downstream Akt3, and suggest that AKT/PTEN signaling should be considered as a therapeutic target in metastatic melanoma

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1446. doi:10.1158/1538-7445.AM2011-1446

Reliability of the MODS assay decentralisation process in three health regions in Peru

OBJECTIVE

To deliver rapid isoniazid (INH) and rifampicin (RMP) drug susceptibility testing (DST) close to the patient, we designed a decentralisation process for the microscopic observation drug susceptibility (MODS) assay in Peru and evaluated its reliability.

METHODS

After 2 weeks of training, laboratory staff processed ≥ 120 consecutive sputum samples each in three regional laboratories. Samples were processed in parallel with MODS testing at an expert laboratory. Blinded paired results were independently analysed by the Instituto Nacional de Salud (INS) according to pre-determined criteria: concordance for culture, DST against INH and RMP and diagnosis of multidrug-resistant tuberculosis (MDR-TB) ≥ 95%, McNemar's P > 0.05, kappa index (κ) ≥ 0.75 and contamination 1-4%. Sensitivity and specificity for MDR-TB were calculated.

RESULTS

The accreditation process for Callao (126 samples, 79.4% smear-positive), Lima Sur (n = 130, 84%) and Arequipa (n = 126, 80%) took respectively 94, 97 and 173 days. Pre-determined criteria in all regional laboratories were above expected values. The sensitivity and specificity for detecting MDR-TB in regional laboratories were >95%, except for sensitivity in Lima Sur, which was 91.7%. Contamination was 1.0-2.3%. Mean delay to positive MODS results was 9.9-12.9 days.

CONCLUSION

Technology transfer of MODS was reliable, effective and fast, enabling the INS to accredit regional laboratories swiftly.

Effect of dietary supplementation with fish oil during the transition period on milk production, plasma metabolites and postpartum anoestrus interval in grazing dairy cows

Inclusion of fish oil (FO) in the diet of dairy cows could improve the energy status and milk yield and reduce the interval from calving to first postpartum ovulation, but the effects may differ depending on the specific period of supplementation. To test these hypotheses, 28 pregnant Holstein heifers were randomly assigned to four treatments in a 2 × 2 factorial design: prepartum oral drench of FO (0 or 140 g/cow.day) for 21 days before calving, and/or postpartum oral drench of FO (0 or 190 g/cow.day) for 21 days after calving. Prepartum, heifers grazed in native pastures with supplements of wheat silage and wheat bran, while postpartum, cows grazed on improved pastures with addition of concentrates and corn silage. No interaction between prepartum and postpartum FO was detected for any variable analysed. Prepartum and postpartum total DM intake, milk yield, protein yield and percentage were not different among treatments. Milk fat percentage (3.83 versus 3.34 ± 0.10%) and yield (0.88 versus 0.73 ± 0.04 kg/day) decreased with postpartum FO but were not affected by prepartum FO. Prepartum and postpartum body condition score and plasma concentration of non-esterified fatty acids and cholesterol were not different among treatments, but urea concentration was higher in cows drenched with FO during prepartum (5.91 versus 4.64 ± 0.35 mM). Proportion of cows that ovulated the dominant follicle of the first postpartum wave and days to first postpartum ovulation, as determined by ovarian ultrasonography, were not affected by drenching with FO, but size of the dominant follicle in the first wave was decreased when FO was drenched only during the pre- or postpartum period compared with drenching in both periods. Dietary supplementation with FO during the postpartum period affected milk fat synthesis but more research is needed to establish its effects on resumption of ovarian activity in grazing dairy cows.

MODS accreditation process for regional reference laboratories in Peru: validation by GenoType® MTBDRplus

SETTING

Although considerable effort has been put into the development and evaluation of new diagnostics for tuberculosis (TB) and multidrug-resistant TB (MDR-TB), little attention has thus far been paid to the technical aspects of initiating quality-assured routine service use. For implementation of the microscopic-observation drug susceptibility (MODS) methodology in the Peruvian reference laboratory network, a laboratory accreditation process was devised; MODS results from an expert reference laboratory (Universidad Peruana Cayetano Heredia [UPCH]) were used as the standard against which implementing laboratory MODS results were judged to ensure that, prior to use for patient care, implementing laboratories achieved the same high performance with MODS as previously demonstrated in the research laboratory.

OBJECTIVE

To evaluate the validity of MODS-based accreditation and the concordance of MODS drug susceptibility testing (DST) with molecular testing.

DESIGN

Head-to-head comparison of MODS DST results from implementing Peruvian regional reference laboratories and the accrediting expert MODS laboratory (UPCH) with GenoType® MTBDRplus DST.

RESULTS

The concordance of phenotypic MODS rifampicin (RMP) DST with GenoType MTBDRplus was respectively 97.4%, 97.9% and 97.1% for the two implementing regional laboratories and UPCH, and respectively 94.7%, 95.7% and 94.6% for isoniazid (INH) DST.

CONCLUSION

High and consistent levels of MODS/MTBDRplus concordance for INH and RMP DST confirm the validity of the use of rapid methods as reference standards for accreditation.

Early regional response of apoptotic activity in newborn piglet brain following hypoxia and ischemia

Responses of selected neuroregulatory proteins that promote (Caspase 3 and Bax) or inhibit (Bcl-2, high Bcl-2/Bax ratio) apoptotic cell death were measured in the brain of piglets subjected to precisely controlled hypoxic and ischemic insults: 1 h hypoxia (decreasing FiO₂ from 21 to 6%) or ischemia (ligation of carotid arteries and hemorrhage), followed by 0, 2 and 4 h recovery with 21% FiO₂. Protein expression was measured in cortex, hippocampus and striatum by Western blot. There were no significant differences in expression of Caspase-3 between sham operated, hypoxic and ischemic groups. There were significant regional differences in expression of Bcl-2 and Bax in response to hypoxia and ischemia. The changes in Bcl-2/Bax ratio were similar for hypoxia and ischemia except for striatum at zero time recovery, with ischemia giving lower ratios than hypoxia. The Bcl-2/Bax ratio was also lower for the striatum than for the other regions of the brain, suggesting this region is the more susceptible to apoptotic injury.