Burkitt-like lymphoma in a pediatric patient with familial adenomatous polyposis

Familial adenomatous polyposis (FAP) is an autosomal dominant condition that predisposes to multiple malignancies, most commonly colorectal carcinoma, but has rarely been associated with lymphoma. We discuss one patient found to have Burkitt-like Lymphoma (BLL) with 11q aberration in the setting of previously undiagnosed FAP. We review the literature of FAP and associated malignancies and the provisional WHO classification of Burkitt-like lymphoma with 11q aberration. Both FAP and Burkitt-like lymphoma with 11q aberration involve perturbation of the MYC network and this may provide insight into a connection between these two diagnoses. However, further study is needed to elucidate if there is an increased risk of BLL and other subtypes of lymphoma among patients with FAP in order to provide optimal counseling and surveillance for patients with FAP.

Abstract 2442: EWS/FLI1 activates GLI1 indirectly through GLI2 in Ewing Sarcoma

GLI1 expression in Ewing tumors has been shown to be enhanced by EWS/FLI1 expression in both model transformation systems and in Ewing cell lines. In Ewing cells, GLI1 has been shown to produce significant phenotypic effects consistent with a role in Ewing tumor formation and propagation. Also consistent with an important role is the demonstrated correspondence between the transcriptional target sets of EWS/FLI1 and of GLI1 in Ewing tumor cells. The principal physiologic developmental regulator of GLI1 is the diffusible Sonic Hedgehog ligand which binds the cell surface tumor suppressor Patched with consequent activation of the transmembrane protein Smoothened. In Ewing tumors, the enhancement of GLI1 expression has been shown to be Hedgehog independent and to occur downstream of Smoothened. Indeed, evidence has been published that EWS/FLI1 directly activates the GLI1 promoter. While there is experimental evidence that GLI1 inhibition may be clinically useful in Ewing tumors, preclinical evidence for one inhibitory approach has been disappointing. Interestingly, direct transcriptional activation of GLI1 has not been demonstrated to be of significance in other most other physiologic or pathologic contexts. We speculated that direct transcriptional activation of GLI1 by EWS/FLI1 might be only part of the story in Ewing tumors.

Since GLI2 is the most potent physiologic transcriptional activator of GLI1, we undertook to investigate the role of GLI2 in Hedgehog/GLI (HH-GLI) signaling in Ewing Tumors. We found that GLI2 is broadly expressed in Ewing tumors. Based on GLI2 overexpression and on shRNA knockdown of GLI2, we found that GLI2 expression increases GLI1 expression in Ewing cell lines. Via GLI2 knockdown, we have found that GLI2 has biologic effects similar to or greater than GLI1 in Ewing cells. Finally, we demonstrate that EWS/FLI1 enhances nuclear localization of GLI2, suggesting an additional indirect mechanism by which EWS/FLI1 activates HH-GLI signaling and GLI1 expression in Ewing tumors.

These data indicate that GLI2 is an active player in HH-GLI pathway activation in Ewing tumors. They also suggest that measures which target GLI2 may have equal or greater efficacy to those aimed at GLI1.

Citation Format: Laura Christensen, William A. May. EWS/FLI1 activates GLI1 indirectly through GLI2 in Ewing Sarcoma. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 2442.

Abstract A43: Therapeutic importance of a long noncoding RNA in Ewing sarcoma

Background: Ewing sarcoma is a highly invasive pediatric bone malignancy with a 20% 5-year survival rate for patients with metastatic disease. The EWS-FLI1 or equivalent fusion gene is detected in 95% of these cases, and functions as a transcription factor that regulates oncogenesis-related gene expression. Various oncoproteins including EWS-FLI1 have been studied at a molecular level to explore their therapeutic potential in order to improve patient outcomes. With a similar aim, we study non-coding genes in Ewing sarcoma that can be targeted using RNA therapeutics.

Methods: Total RNA from 500 tissues including over 100 primary Ewing, other cancers, normal tissues, and modified Ewing cell lines were run on Affymetrix Human Exon microarrays. RNA-seq data was generated on a pair of primary and metastatic Ewing cell lines. Data were analyzed using Genetrix®, Partek®, and Ingenuity Pathway Analysis®. Functional studies on Ewing cell lines were performed using various RNAi techniques and viral transductions followed by quantitative PCR. Chromatin immunoprecipitation (ChIP) was performed to detect direct interactions of the RNA. Tail vein injection model was developed to study tumor metastasis model in mice.

Results: Expression profiling results indicated that several non-coding transcripts had a strong association with Ewing sarcoma. Molecular characterization of one such transcript, AK057037 (also known as FEZF1-AS), identified it as a multi-exonic, polyadenylated , long non-coding RNA (lncRNA) with multiple expressed isoforms. Like many other Ewing sarcoma associated biomarkers, EWS-FLI1 directly regulated this lncRNA by binding to the GGAA microsatellite region in its promoter. Increased stable expression of this transcript led to a statistically significant increase in anchorage independence. RNAi mediated decrease in its expression reduced the invasiveness of Ewing sarcoma cell lines. In vivo studies using AK057037-overexpressing cells showed increased tumor cell engraftment and growth in the mice liver. Pathway analysis of expression profiling data on the AK057037-knockdown cells identified cellular adhesion and movement pathways. RNA-seq analysis showed increased transcriptional activity in the metastatic cell line when compared to the primary. RNA-IP studies showed that AK057037 was bound to EZH2, a methyltransferase in the polycomb repressor complex 2 (PRC2). ChIP assays using histone antibodies showed changes in methylation pattern in promoter regions of genes affected by the lncRNA knockdown. H3K27me3 marks correlated with increased repression of metastatic genes on knockdown of the transcript.

Conclusion: AK057037 is a lncRNA that is highly expressed in Ewing sarcoma. It is directly regulated by the chimeric oncogene, EWS-FLI1. The lncRNA functions as an oncogene and promotes metastasis in this tumor. Its association with the PRC2 complex leads to methylation changes in promoters of genes that are involved in cell migration. Finally, AK057037 is a functional lncRNA that influences Ewing sarcoma pathogenesis by its genetic and epigenetic interactions and has the potential to be developed into a therapeutic target to improve survival of patients with metastatic disease.

Citation Format: Sheetal A. Mitra, Anirban P. Mitra, Jonathan D. Buckley, William A. May, Philipp Kapranov, Robert J. Arceci, Timothy J. Triche. Therapeutic importance of a long noncoding RNA in Ewing sarcoma. [abstract]. In: Proceedings of the AACR Special Conference on Pediatric Cancer at the Crossroads: Translating Discovery into Improved Outcomes; Nov 3-6, 2013; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2013;74(20 Suppl):Abstract nr A43.

Abstract 4973: Long non-coding RNA promotes metastatic behavior in Ewing sarcoma

Ewing sarcoma (ES) is a highly malignant bone and soft tissue tumor with a 20% 5-year survival rate for patients with metastatic disease. Further, even clinically localized tumors are not successfully treated with local therapy like surgery and radiation, indicative of sub-clinical dissemination at presentation, as noted by James Ewing in his original papers. Extensive research has led to better understanding of the molecular pathogenesis of the disease but few discoveries have been successfully translated into improving treatment of ES patients. Our aim is to identify and characterize novel genomic features that can be developed into therapeutic targets for metastatic ES. This study documents the importance of one such ES-specific long non-coding RNA (lncRNA) in invasion and metastasis.

Expression data from over a hundred ES primary tumors were compared to normal adult tissues as well as other types of pediatric and adult cancers to identify ES-specific coding and non-coding RNA transcripts. One highly expressed lncRNA, AK057037, was exclusively associated with ES. Further characterization of the transcript using loss of function studies showed that this 2.6 kb, 7 exon, polyadenylated RNA was directly regulated by EWS-FLI1, the chimeric oncoprotein that is the hallmark of ES and a major driver of tumorigenesis. In vitro, knockdown of the lncRNA resulted in reduced invasiveness of ES cells. In vivo, cells over-expressing the transcript showed statistically significant increase in metastasis compared to controls. Downstream targets included cell adhesion molecules such as cadherins and extracellular matrix proteins. Immunoprecipitation (IP) showed binding of the lncRNA to its direct targets. Binding of the lncRNA to other regulatory proteins also affected more global changes including promoter methylation and subsequent modulation of the downstream targets.

We conclude that this lncRNA is a highly specific and unique ES biomarker. It acts as an oncogene by promoting invasion and metastasis of ES cells by controlling expression of genes involved in these pathways. Understanding this additional regulation by non-coding RNAs will enable development of multi-modal therapies that may prove to be more effective in treating aggressive disease.

Citation Format: Sheetal A. Mitra, Anirban P. Mitra, Jonathan D. Buckley, William A. May, Philipp Kapranov, Robert J. Arceci, Timothy J. Triche. Long non-coding RNA promotes metastatic behavior in Ewing sarcoma. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4973. doi:10.1158/1538-7445.AM2014-4973

Characterization and drug resistance patterns of Ewing's sarcoma family tumor cell lines

Despite intensive treatment with chemotherapy, radiotherapy and surgery, over 70% of patients with metastatic Ewing's Sarcoma Family of Tumors (EFT) will die of their disease. We hypothesize that properly characterized laboratory models reflecting the drug resistance of clinical tumors will facilitate the application of new therapeutic agents to EFT. To determine resistance patterns, we studied newly established EFT cell lines derived from different points in therapy: two established at diagnosis (CHLA-9, CHLA-32), two after chemotherapy and progressive disease (CHLA-10, CHLA-25), and two at relapse after myeloablative therapy and autologous bone marrow transplantation (post-ABMT) (CHLA-258, COG-E-352). The new lines were compared to widely studied EFT lines TC-71, TC-32, SK-N-MC, and A-673. These lines were extensively characterized with regard to identity (short tandem repeat (STR) analysis), p53, p16/14 status, and EWS/ETS breakpoint and target gene expression profile. The DIMSCAN cytotoxicity assay was used to assess in vitro drug sensitivity to standard chemotherapy agents. No association was found between drug resistance and the expression of EWS/ETS regulated genes in the EFT cell lines. No consistent association was observed between drug sensitivity and p53 functionality or between drug sensitivity and p16/14 functionality across the cell lines. Exposure to chemotherapy prior to cell line initiation correlated with drug resistance of EFT cell lines in 5/8 tested agents at clinically achievable concentrations (CAC) or the lower tested concentration (LTC): (cyclophosphamide (as 4-HC) and doxorubicin at CAC, etoposide, irinotecan (as SN-38) and melphalan at LTC; P<0.1 for one agent, and P<0.05 for four agents. This panel of well-characterized drug-sensitive and drug-resistant cell lines will facilitate in vitro preclinical testing of new agents for EFT.

Simultaneous colonic adenocarcinoma and medulloblastoma in a 12-year-old with biallelic deletions in PMS2

We describe a 12-year-old girl, simultaneously presenting with colonic adenocarcinoma and medulloblastoma from bialleic deletions in the mismatch repair gene PMS2. Her distinctive physical and clinical findings are characteristic of constitutional mismatch repair deficiency syndrome. Earlier recognition of such findings may permit better screening and more effective treatment.

Abstract PR04: Genomic and epigenomic interactions of an Ewing sarcoma-specific long noncoding RNA

Ewing sarcoma is a highly invasive pediatric bone malignancy with a 30% 5-year survival rate for patients with metastatic disease. The EWS-FLI1 fusion gene is detected in 90% of these cases, and functions as a transcription factor that regulates oncogenesis-related gene expression. The functions of EWS-FLI1 and other oncogenes have been explored in the past to detect potential therapeutic targets.

Here we report the functions and interactions of a long intergenic non-coding RNA (lincRNA) that is unique to Ewing sarcoma. Gene expression profiling studies identified a significant association of lincRNA, AK057037, with Ewing sarcoma. Chromatin immunoprecipitation (ChIP) and functional studies with EWS-FLI1 detected direct regulation of this multi-exonic, multivariant lincRNA by EWS-FLI1. Comparative RNA-seq analysis on primary and metastatic tumor cell lines showed increased transcriptional activity in the metastatic cell line. In vitro and in vivo functional studies with the lincRNA confirmed its role as an oncogene in promoting anchorage independence and metastasis of the Ewing sarcoma cell lines and xenograft models, respectively. Further, ChIP studies showed that AK057037 was bound to Ezh2, a methyltransferase in the polycomb repressor complex 2 (PRC2). ChIP-seq using histone antibodies showed changes in methylation pattern in promoter regions of genes affected by the lincRNA knockdown.

In conclusion, the lincRNA AK057037 behaves as an oncogene in Ewing sarcoma. Its association with the PRC2 complex allows for chromatin remodeling such that it promotes metastasis by perturbing transcription of genes involved in migration in this malignancy.

This abstract is also presented as Poster A33.

Citation Format: Sheetal A. Mitra, Anirban P. Mitra, Jonathan D. Buckley, William A. May, Philipp Kapranov, Robert A. Arceci, Timothy J. Triche. Genomic and epigenomic interactions of an Ewing sarcoma-specific long noncoding RNA. [abstract]. In: Proceedings of the AACR Special Conference on Chromatin and Epigenetics in Cancer; Jun 19-22, 2013; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2013;73(13 Suppl):Abstract nr PR04.

Abstract 1823: Influence of a long non-coding RNA on epigenetic, genetic and phenotypic changes in Ewing sarcoma

Background: Ewing sarcoma is a highly invasive pediatric bone malignancy with a 30% 5-year survival rate for patients with metastatic disease. The EWS-FLI1 fusion gene is detected in 90% of these cases, and functions as a transcription factor that regulates oncogenesis-related gene expression. The functions of EWS-FLI1 and other oncogenes have been explored in the past to detect potential therapeutic targets. With a similar aim, this study looks into the rapidly evolving non-coding genome of Ewing sarcoma. Methods: Total RNA from 500 tissues including over 100 primary Ewing, other cancers, normal tissues, and modified Ewing cell lines were run on Affymetrix Human Exon microarrays. RNA-seq data was generated on a pair of primary and metastatic Ewing cell lines. Data were analyzed using Genetrix®, Partek®, Ingenuity Pathway Analysis (IPA®) and iReport™. Functional studies on Ewing cell lines were performed using various RNAi techniques and viral transductions followed by quantitative PCR. Chromatin immunoprecipitation (ChIP) was performed to detect direct interactions of the RNA. Tail vein injection model was developed to study tumor metastasis model in mice. Results: Expression profiling showed that many unannotated transcripts were more significantly associated with Ewing sarcoma than coding genes. Molecular characterization of one such transcript, AK057037, identified it as a multi-exonic, multivariant, polyadenylated, long non-coding RNA (lncRNA). It was not expressed in other tumors or normal adult tissue and was poorly conserved across various vertebrates and lower organisms. The chimeric oncoprotein, EWS-FLI1, directly regulated AK057037 expression by binding to the GGAA microsatellite region in its promoter. Decrease in the lncRNA expression significantly reduced invasive capability of Ewing cells while an increase in expression increased anchorage independence. RNA-seq analysis showed increased transcriptional activity in the metastatic cell line. Pathway analysis on expression profiling data on the AK057037-knockdown cells detected involvement of cellular adhesion and movement pathways. In vivo studies using AK057037-overexpressing cells showed increased tumor cell engraftment and growth in the mice liver. ChIP studies showed that AK057037 was bound to Ezh2, a methyltransferase in the polycomb repressor complex 2 (PRC2). ChIP assays using histone antibodies showed changes in methylation pattern in promoter regions of genes affected by the lncRNA knockdown. Conclusion: AK057037, a lncRNA is significantly upregulated in Ewing sarcoma. Its direct regulation by EWS-FLI1 drives its function as an oncogene and promotes metastasis of the tumor cells, thus helping with the tumor pathogenesis. Its association with the PRC2 complex and perturbation of methylation status of its downstream effectors suggest chromatin modifying functions of AK057037.

Citation Format: Sheetal A. Mitra, Anirban P. Mitra, Jonathan D. Buckley, William A. May, Philipp Kapranov, Robert J. Arceci, Timothy J. Triche. Influence of a long non-coding RNA on epigenetic, genetic and phenotypic changes in Ewing sarcoma. [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 1823. doi:10.1158/1538-7445.AM2013-1823

FOXM1 is an oncogenic mediator in Ewing Sarcoma

Ewing Family Tumors (Ewing Sarcoma and peripheral Primitive Neuroectodermal Tumor) are common bone and soft tissue malignancies of childhood, adolescence and young adulthood. Chromosomal translocation in these tumors produces fusion oncogenes of the EWS/ETS class, with EWS/FLI1 being by far the most common. EWS/ETS chimera are the only well established driver mutations in these tumors and they function as aberrant transcription factors. Understanding the downstream genes whose expression is modified has been a central approach to the study of these tumors. FOXM1 is a proliferation associated transcription factor which has increasingly been found to play a role in the pathogenesis of a wide range of human cancers. Here we demonstrate that FOXM1 is expressed in Ewing primary tumors and cell lines. Reduction in FOXM1 expression in Ewing cell lines results in diminished potential for anchorage independent growth. FOXM1 expression is enhanced by EWS/FLI1, though, unlike other tumor systems, it is not driven by expression of the EWS/FLI1 target GLI1. Thiostrepton is a compound known to inhibit FOXM1 by direct binding. We show that Thiostrepton diminishes FOXM1 expression in Ewing cell lines and this reduction reduces cell viability through an apoptotic mechanism. FOXM1 is involved in Ewing tumor pathogenesis and may prove to be a useful therapeutic target in Ewing tumors.

Human osteosarcoma CD49f(-)CD133(+) cells: impaired in osteogenic fate while gain of tumorigenicity

The biological relationships among self-renewal, tumorigenicity, and lineage differentiation of human osteosarcoma-initiating cells (OSIC) remain elusive, making it difficult to identify and distinguish OSIC from osteosarcoma-forming cells (OSFC) for developing OSIC-targeted therapies. Using a new inverse lineage tracking strategy coupled with serial human-to-mouse xenotransplantation, we identified a subpopulation of osteosarcoma cells with OSIC-like properties and sought to distinguish them from their progeny, OSFC. We found that serial transplantation of cells from different osteosarcoma cell lines and primary osteosarcoma tissues progressively increased the CD49f⁺ subpopulation composing the bulk of the osteosarcoma mass. These CD49f⁺ cells displayed characteristics of OSFC: limited in vivo tumorigenicity, weak lineage differentiation, more differentiated osteogenic feature, and greater chemo-sensitivity. By contrast, their parental CD49f⁻CD133⁺ cells had an inhibited osteogenic fate, together with OSIC-like properties of self-renewal, strong tumorigenicity, and differentiation to CD49f⁺ progeny. Hence, the CD49f⁻CD133⁺ phenotype appears to identify OSIC-like cells that possess strong tumorigenicity correlated with an impaired osteogenic fate and the ability to initiate tumor growth through generation of CD49f⁺ progeny. These findings advance our understanding of OSIC-like properties and, for the first time, provide a much-needed distinction between OSIC and OSFC in this cancer.

Abstract 1288: GLI2 is a significant determinant of HH-GLI pathway activaton in Ewing sarcoma

Ewing Sarcoma is an aggressive bone and soft tissue malignancy of children, adolescents and young adults. Non-canonical activation of the Hedgehog-GLI pathway by the Ewing specifc EWS/FLI1 transcription factor has been shown to mediate important aspects of tumor phenotype. While evidence regarding the role of EWS/FLI1 in direct activation has been published, no one has yet investigated the role of other pathway components in Ewing tumors. Physiologically, GLI2 is the principal transcriptional activator of GLI1 and substantial amounts of GLI2 can be demonstrated in Ewing tumors and cell lines. So we hypothesized that GLI2 may also function in Ewing cells to help to regulate GLI1 and Hedgehog-GLI pathway activaton. Since GLI2 can be targeted by pharmacologic means, understanding its role in Ewing tumors is of potential significance. We demonstrate that GLI2 is expressed at significant levels in Ewing tumors. Furthermore, we show by overexpression studies, that GLI2 overexpression augments expression of both GLI1 and other pathway targets in Ewing cell lines. By using shRNA, we also demonstrate that knockdown of GLI2 expression has the expected effect of diminishing GLI 1 expression in Ewing lines. Finally, we show that treatment with GLI inhibitors also diminishes GLI2 activation of GLI1. Overall, these data indicate that GLI2 in Ewing cells exists in an activator state in Ewing cells and that pharmacologic means of targeting GLI2 may be an effective strategy for targeted therapy.

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 1288. doi:1538-7445.AM2012-1288

GLI1 is a central mediator of EWS/FLI1 signaling in Ewing tumors

The Ewing Sarcoma Family Tumors (ESFT) consist of the classical pathologic entities of Ewing Sarcoma and peripheral Primitive Neuroectodermal Tumor. Occurring largely in the childhood through young adult years, these tumors have an unsurpassed propensity for metastasis and have no defined cell of origin. The biology of these aggressive malignancies centers around EWS/FLI1 and related EWS/ETS chimeric transcription factors, which are largely limited to this tumor class. Much progress has been made in the identification of a network of loci whose expression is modulated by EWS/FLI1 and its congeners. To date, little progress has been made in reconstructing the sequence of direct and indirect events that produce this network of modulated loci. The recent identification of GLI1 as an upregulated target of EWS/ETS transcription factors suggests a target which may be a more central mediator in the ESFT signaling network. In this paper, we further define the relationship of EWS/FLI1 expression and GLI1 upregulation in ESFT. This relationship is supported with data from primary tumor specimens. It is consistently observed across multiple ESFT cell lines and with multiple means of EWS/FLI1 inhibition. GLI1 inhibition affects tumor cell line phenotype whether shRNA or endogenous or pharmacologic inhibitors are employed. As is seen in model transformation systems, GLI1 upregulation by EWS/FLI1 appears to be independent of Hedgehog stimulation. Consistent with a more central role in ESFT pathogenesis, several known EWS/FLI1 targets appear to be targeted through GLI1. These findings further establish a central role for GLI1 in the pathogenesis of Ewing Tumors.

E-cadherin cell-cell adhesion in ewing tumor cells mediates suppression of anoikis through activation of the ErbB4 tyrosine kinase

Ability to grow under anchorage-independent conditions is one of the major hallmarks of transformed cells. Key to this is the capacity of cells to suppress anoikis, or programmed cell death induced by detachment from the extracellular matrix. To model this phenomenon in vitro, we plated Ewing tumor cells under anchorage-independent conditions by transferring them to dishes coated with agar to prevent attachment to underlying plastic. This resulted in marked up-regulation of E-cadherin and rapid formation of multicellular spheroids in suspension. Addition of calcium chelators, antibodies to E-cadherin (but not to other cadherins or beta(1)-integrin), or expression of dominant negative E-cadherin led to massive apoptosis of spheroid cultures whereas adherent cultures were unaffected. This correlated with reduced activation of the phosphatidylinositol 3-kinase-Akt pathway but not the Ras-extracellular signal-regulated kinase 1/2 cascade. Furthermore, spheroid cultures showed profound chemoresistance to multiple cytotoxic agents compared with adherent cultures, which could be reversed by alpha-E-cadherin antibodies or dominant negative E-cadherin. In a screen for potential downstream effectors of spheroid cell survival, we detected E-cadherin-dependent activation of the ErbB4 receptor tyrosine kinase but not of other ErbB family members. Reduction of ErbB4 levels by RNA interference blocked Akt activation and spheroid cell survival and restored chemosensitivity to Ewing sarcoma spheroids. Our results indicate that anchorage-independent Ewing sarcoma cells suppress anoikis through a pathway involving E-cadherin cell-cell adhesion, which leads to ErbB4 activation of the phosphatidylinositol 3-kinase-Akt pathway, and that this is associated with increased resistance of cells to cytotoxic agents.

He's got a gun! Weapons in the emergency room--you can survive!

With the increasing amount of violence prevalent in our society, it is inevitable that this violence will enter emergency departments. Nurses are increasingly likely to see guns and other deadly weapons in the emergency department. The purpose of this article is to explain how a firearm works and how to safely handle and store the weapon until someone with more training can take possession of the weapon.

EWS/FLI function varies in different cellular backgrounds

EWS/FLI and other EWS/ets chimeric transcription factors play a central role in the biology of the Ewing family tumors. As with many oncogenes, EWS/FLI biologic activity can be demonstrated in a limited range of cellular contexts. To investigate the causes of this restriction, we demonstrate that two immortalized fibroblast lines resistant to EWS/FLI transformation, Rat1 and Yal7, express stable levels of EWS/FLI protein. Despite their resistance to EWS/FLI, Rat1 and Yal7 can be transformed by the potent EWS/FLI downstream mediator PDGF-C. In contrast to NIH3T3, the EWS/FLI resistant lines show no upregulation of PDGF-C in response to EWS/FLI, demonstrating differential EWS/FLI function in different cellular backgrounds. This phenomenon of differential function can also be demonstrated for several other NIH3T3 targets of EWS/FLI. Despite the correlation between anchorage-independent growth and PDGF-C induction, PDGF-C does not fully reproduce all aspects of the EWS/FLI phenotype in NIH3T3 cells. These results further point to the importance of PDGF-C in mediating EWS/FLI in vitro transformation and suggest caution in assuming that a transcription factor will produce identical effects in different cellular backgrounds.

Dominant negative PDGF-C inhibits growth of Ewing family tumor cell lines

Nearly all cases of Ewing Family Tumors (EFT) harbor chimeric EWS/ETS transcription factors which are thought to aberrantly regulate transcriptional targets of phenotypic consequence. We have recently demonstrated that EWS/ETS proteins up-regulate platelet derived growth factor-C (PDGF-C), a novel transforming growth factor. To determine if PDGF-C signaling contributes to the malignant phenotype of EFT cell lines, we attempted to disrupt this presumed autocrine loop. AG1296, a PDGF receptor selective tyrosine kinase inhibitor, markedly inhibits anchorage-independent growth in an EFT cell line. To effect specific disruption, we have developed a dominant negative form of PDGF-C which is appropriately secreted and processed. This mutant has greatly reduced activity as a PDGF receptor agonist. When co-expressed with PDGF-C in a fibroblast transformation model, this dominant negative dramatically inhibits anchorage-independent growth. When this mutant is expressed in EFT cell lines, there is a similar reduction in anchorage-independent growth. This demonstrates that specific inhibition of PDGF-C signaling in EFT cell lines partially reverts their phenotype. These data support a significant role of PDGF-C in the biology of EFT. They also suggest that PDGF-C driven signaling may be a possible therapeutic target of more clinically relevant tyrosine kinase inhibitors.

PDGF-C is an EWS/FLI induced transforming growth factor in Ewing family tumors

The aberrant transcription factors associated with many human malignancies function by deregulation of tumorigenic pathways. However, identification of these pathways has come slowly. Virtually all cases of Ewing's Sarcoma and peripheral Primitive Neuroectodermal Tumor (PNET) are associated with aberrant transcription factors which fuse amino-terminal EWS with the DNA binding moiety of an ETS transcription factor (FLI-1 in 90% of cases). Attempts to identify the downstream targets of these chimeras in the Ewing Family Tumors (EFT) on the basis of differential gene regulation have produced little association with tumor biology. As an alternative approach, we have used highly efficient retroviral systems to biologically screen cDNA derived from cells transformed by EWS/FLI-1. We have identified the recently described PDGF-C as target of EWS/ETS transcriptional deregulation. This transcriptional deregulation is specific to EWS/FLI. PDGF-C possesses substantial biologic activity in vitro and in vivo. It is expressed in EFT cell lines and in primary tumors. Within these EFT cell lines, PDGF-C expression is dependent upon EWS/FLI activity. These results suggest that PDGF-C may be a significant mediator of EWS/FLI driven oncogenesis.

Short report: documentation of iodine deficiency in Haitian schoolchildren: implication for lymphatic filariasis elimination in Haiti

In this study we documented unexpected moderate-to-severe iodine deficiency in Haitian schoolchildren although they live in a coastal community where presumably they have access to iodine-containing seafood. This fact combined with the lack of an iodized salt supply and endemic lymphatic filariasis makes community distribution of diethylcarbamazine-fortified, iodized salt an attractive strategy for elimination of lymphatic filariasis and iodine deficiency disorders in this area of Haiti. Combining lymphatic filariasis elimination with other public health interventions is one strategy to increase its public health benefit and maximize the impact of limited public health resources.

EWS/FLI1-induced manic fringe renders NIH 3T3 cells tumorigenic

EWS/FLI1, a fusion gene found in Ewing's sarcoma, encodes a transcriptional regulator and promotes cellular transformation by modulating the transcription of specific target genes. We have found that EWS/FLI1 and structurally related fusion proteins upregulate manic fringe (MFNG), a recently described member of the Fringe gene family instrumental in somatic development. MFNG is also expressed in human tumour-derived cell lines expressing EWS/FLI1. Overexpression of MFNG in NIH 3T3 cells renders them tumorigenic in mice with severe combined immunodeficiency disease (SCID). These data demonstrate that part of the oncogenic effect of EWS/FLI1 is to transcriptionally deregulate a member of a family of morphogenic genes.

Effect of hemolysis on serum retinol as assessed by direct fluorometry

To assess the effect of hemolysis on serum retinol concentrations determined by direct fluorometry, we assayed 196 blood samples from children 6-72-mo of age with various grades of hemolysis for serum retinol by both fluorescence and HPLC. Mean serum retinol concentrations determined by HPLC did not differ significantly according to hemolysis grade; however, fluorometric values did. Additionally, serum retinol concentrations obtained from HPLC and those obtained from direct fluorometry were significantly different in samples with severe hemolysis. Multivariate-regression analysis showed that hemolysis grade was a significant predictor of the difference in mean serum retinol values determined by the two methods. Although severe hemolysis interfered with determinations of serum retinol by direct fluorometry, this method is still a viable choice for field studies of vitamin A status.

Better maternal outcomes are achieved with dexamethasone therapy for postpartum HELLP (hemolysis, elevated liver enzymes, and thrombocytopenia) syndrome

OBJECTIVE

Our purpose was to determine whether the routine initiation of dexamethasone therapy in patients with postpartum HELLP (hemolysis, elevated liver enzymes, and thrombocytopenia) syndrome produces specific and general therapeutic benefits.

STUDY DESIGN

In this retrospective, analytic study the puerperal courses of 43 women with postpartum HELLP syndrome who were treated with dexamethasone were compared with those of 237 similar patients who did not receive corticosteroids. Dexamethasone 10 mg intravenously at 12-hour intervals was given until disease remission was noted in treated patients, at which time up to two additional 5 mg intravenous doses were given at 12-hour intervals.

RESULTS

The two patient groups were similar in regard to mode of delivery, gestational age, parity, and frequency of eclampsia. Compared with control subjects, dexamethasone-treated postpartum patients were more ill with significantly higher (p < 0.05) admission mean arterial blood pressure, higher serum uric acid level, and severe proteinuria. Dexamethasone administration was associated with a more rapid normalization of platelet counts and lactic dehydrogenase values. Most impressive was a clinically significant reduction of indicated transfusion and respiratory therapy, invasive hemodynamic monitoring, infectious or bleeding-related morbidity, and length of postpartum hospital course.

CONCLUSIONS

Patients who received dexamethasone for postpartum-onset HELLP syndrome experienced a shorter disease course, faster recovery, less morbidity, and less need for other interventionist therapy compared with patients with HELLP syndrome who did not receive dexamethasone.

Validation of a simple, manual urinary iodine method for estimating the prevalence of iodine-deficiency disorders, and interlaboratory comparison with other methods

The measurement of urinary iodine in population-based surveys provides a biological indicator of the severity of iodine-deficiency disorders. We describe the steps performed to validate a simple, inexpensive, manual urinary iodine acid digestion method, and compare the results using this method with those of other urinary iodine methods. Initially, basic performance characteristics were evaluated: the average recovery of added iodine was 100.4 +/- 8.7% (mean +/- SD), within-assay precision (CV) over the assay range 0-0.95 mumol/L (0-12 micrograms/dL) was < 6%, between-assay precision over the same range was < 12%, and assay sensitivity was 0.05 mumol/L (0.6 microgram/dL). There were no apparent effects on the method by thiocyanate, a known interfering substance. In a comparison with five other methods performed in four different laboratories, samples were collected to test the method performance over a wide range of urinary iodine values (0.04-3.7 mumol/L, or 0.5-47 micrograms/dL). There was a high correlation between all methods and the interpretation of the results was consistent. We conclude that the simple, manual acid digestion method is suitable for urinary iodine analysis.

EAT-2 is a novel SH2 domain containing protein that is up regulated by Ewing's sarcoma EWS/FLI1 fusion gene

The EWS/FLI1 fusion protein is created by the translocation between chromosomes 11 and 22 that appears in most Ewing's sarcomas. This chimeric protein has been demonstrated to be an aberrant transcription factor. Genes up regulated by EWS/FLI1 but not by full-length FLI1 were identified by representational difference analysis (RDA). We have characterized a novel gene, EWS/FLI1 activated transcript 2 (EAT-2) that was cloned from a murine cDNA library using a differentially expressed RDA fragment. EAT-2 expression is seen within 4-8 h of EWS/FLI1 induction. Its expression correlates with transformation of NIH3T3 cells by chimeric proteins related to EWS/FLI1 but not by unrelated genes. EAT-2 is expressed in normal murine tissues and contains a unique but biochemically functional SH2 domain. An homologous sequence in the human genome has been identified and mapped to chromosome 1q22. Human EAT-2 transcripts were identified by reverse transcriptase-polymerase chain reaction (RT-PCR) in Ewing's sarcoma cell tumour cell lines. EAT-2's unique structure and correlation with transformation make it a candidate for playing a role in the transformation of NIH3T3 cells and the oncogenesis of Ewing's sarcoma.

Identification of target genes for the Ewing's sarcoma EWS/FLI fusion protein by representational difference analysis

The EWS/FLI-1 fusion gene results from the 11;22 chromosomal translocation in Ewing's sarcoma. The product of the gene is one of a growing number of structurally altered transcription factors implicated in oncogenesis. We have employed a subtractive cloning strategy of representational difference analysis in conjunction with a model transformation system to identify genes transcribed in response to EWS/FLI. We have characterized eight transcripts that are dependent on EWS/FLI for expression and two transcripts that are repressed in response to EWS/FLI. Three of the former were identified by sequence analysis as stromelysin 1, a murine homolog of cytochrome P-450 F1 and cytokeratin 15. Stromelysin 1 is induced rapidly after expression of EWS/FLI, suggesting that the stromelysin 1 gene may be a direct target gene of EWS/FLI. These results demonstrate that expression of EWS/FLI leads to significant changes in the transcription of specific genes and that these effects are at least partially distinct from those caused by expression of germ line FLI-1. The representational difference analysis technique can potentially be applied to investigate transformation pathways activated by a broad array of genes in different tumor systems.

Treatment of verapamil overdose with glucagon in dogs

STUDY OBJECTIVE

The purpose of this study was to evaluate the effectiveness of glucagon as a treatment for the hemodynamic effects of verapamil overdose in a canine model.

DESIGN

The study was performed in a nonblinded, controlled animal model.

INTERVENTIONS

Pentobarbital-anesthetized and instrumented dogs were maintained and observed for 60 minutes or until death. All animals were overdosed with 15 mg/kg i.v. verapamil over 30 minutes. Mean arterial pressure, heart rate, ECG, and cardiac output were monitored. The experimental group received a 2.5 mg glucagon i.v. bolus followed by a glucagon drip at 2.5 mg/hr. The control group received an equal volume of i.v. normal saline solution in the same fashion. Analysis was performed with the Dunnett and Tukey-Kramer methods, with alpha set at .05.

RESULTS

There were eight experimental and seven control animals, with mortality rates of 0% and 29%, respectively. The experimental group had increases in cardiac output and heart rate that were statistically significant at 45 and 60 minutes compared with those of the control group. In addition, there was a significant difference in heart rate at 30 minutes. No difference was noted between the groups for mean arterial pressure.

CONCLUSION

Glucagon appears to reverse both the bradycardia and the depressed cardiac output associated with verapamil overdose in a canine model.

Multiple domains mediate transformation by the Ewing's sarcoma EWS/FLI-1 fusion gene

The (11;22) chromosomal translocation found in Ewing's sarcoma and related tumors fuses the amino terminus of the EWS protein to the DNA-binding domain of the FLI-1 transcription factor. In contrast to normal FLI-1, the EWS/FLI-1 fusion transforms NIH3T3 cells and this activity requires both EWS and FLI-1 sequences. Reporter gene assays showed that the portion of EWS fused to FLI-1 encodes a strong transcriptional activation domain. To determine whether this function is necessary for transformation by EWS/FLI-1, deletion analysis of EWS was performed. We found that the EWS domain could be functionally subdivided into two regions: (i) an amino terminal domain (domain A) which transforms efficiently when fused to FLI-1 but has little transactivation activity in a model system and (ii) a distal region (domain B) which transactivates efficiently but transforms less efficiently when fused to FLI-1. Replacement of the EWS domain with known heterologous transcriptional activation domains yielded chimeric FLI-1 fusions that in some instances could transform NIH3T3 cells. Finally we demonstrate that EWS/FLI-1 and related FLI-1 chimeras are able to cooperate with another transcription factor to activate a model reporter gene. These results further demonstrate that EWS/FLI-1 is an aberrant transcription factor and suggest that the EWS domain mediates important protein-protein interactions with other factors resulting in the transcriptional modulation of target genes.

Exacerbation of verapamil-induced hyperglycemia with glucagon

To evaluate the effects of verapamil intoxication and glucagon treatment on blood glucose levels in an intact canine model, 15 mg/kg verapamil was administered intravenously over a 30-minute period to mongrel dogs under pentobarbital anesthesia. Animals in the experimental group subsequently were administered 2.5 mg glucagon followed by an infusion of 2.5 mg per hour; control group animals were administered an equal volume of saline. Blood glucose was assessed before verapamil administration (baseline), and at 10 minutes (time 10) and 60 minutes (time 60) after completion of the verapamil infusion. Glucose values were compared between control and experimental groups using Dunnett's method (P = .05). At baseline, no animals were hyperglycemic and there was no difference in glucose levels. Animals in both groups became hyperglycemic after verapamil infusion. At time 10, the experimental group had significantly higher glucose levels (265 +/- 17.1 mg/dL) than the control group (209 +/- 18.3 mg/dL). By time 60, there was no significant difference between glucose values in the control (262 +/- 31.4) and experimental (246 +/- 24.8) groups. It was concluded that verapamil intoxication consistently resulted in hyperglycemia in this model. Glucagon therapy was associated with an early but nonsustained exacerbation of verapamil-induced hyperglycemia.

The Ewing's sarcoma EWS/FLI-1 fusion gene encodes a more potent transcriptional activator and is a more powerful transforming gene than FLI-1

EWS/FLI-1 is a chimeric protein formed by a tumor-specific 11;22 translocation found in both Ewing's sarcoma and primitive neuroectodermal tumor of childhood. EWS/FLI-1 has been shown to be a potent transforming gene, suggesting that it plays an important role in the genesis of these human tumors. We now demonstrate that EWS/FLI-1 has the characteristics of an aberrant transcription factor. Subcellular fractionation experiments localized the EWS/FLI-1 protein to the nucleus of primitive neuroectodermal tumor cells. EWS/FLI-1 specifically bound in vitro an ets-2 consensus sequence similarly to normal FLI-1. When coupled to a GAL4 DNA-binding domain, the amino-terminal EWS/FLI-1 region was a much more potent transcriptional activator than the corresponding amino-terminal domain of FLI-1. Finally, EWS/FLI-1 efficiently transformed NIH 3T3 cells, but FLI-1 did not. These data suggest that EWS/FLI-1, functioning as a transcription factor, leads to a phenotype dramatically different from that of cells expressing FLI-1. EWS/FLI-1 could disrupt normal growth and differentiation either by more efficiently activating FLI-1 target genes or by inappropriately modulating genes normally not responsive to FLI-1.

Ewing sarcoma 11;22 translocation produces a chimeric transcription factor that requires the DNA-binding domain encoded by FLI1 for transformation

The 11;22 chromosomal translocation specifically linked to Ewing sarcoma and primitive neuroectodermal tumor results in a chimeric molecule fusing the amino-terminal-encoding portion of the EWS gene to the carboxyl-terminal DNA-binding domain encoded by the FLI1 gene. We have isolated a fourth EWS-FLI1 fusion cDNA that is structurally distinct from the three forms previously described. To determine the transforming activity of this gene, alternative forms of the EWS-FLI1 fusion were transduced into NIH 3T3 cells. Cells expressing either type 1 or type 4 fusion constructs formed foci in culture and colonies in soft agar, indicating that EWS-FLI1 is a transforming gene. EWS-FLI1 deletion mutants were created to map functionally the critical regions within the chimera. Deletion of either the EWS domain or the FLI1 corresponding to the DNA-binding domain totally abrogated the ability for EWS-FLI1 to transform 3T3 cells. These data indicate that the oncogenic effect of the 11;22 translocation is caused by the formation of a chimeric transcription factor. Formation of chimeric transcription factors has now been demonstrated to promote tumors of both neuroectodermal and hematopoietic origin, suggesting that this may be a common mechanism in human carcinogenesis.