ETS2 overexpression in transgenic models and in Down syndrome predisposes to apoptosis via the p53 pathway

Microarray analysis identifies altered regulation of nuclear receptor family members in the pre-disease state of multiple sclerosis

Molecular mechanisms that influence susceptibility to multiple sclerosis are poorly understood. We analyzed peripheral blood gene expression profiles in nine healthy subjects up to nine years before the onset of multiple sclerosis in comparison with 11 age-, gender-, and origin-matched healthy subjects who remained multiple sclerosis-free, and 31 subjects during the first clinical episode of multiple sclerosis. Within the 1051 highly variable genes that differentiated between multiple sclerosis-to-be and multiple sclerosis-free subjects, we identified activation of TCR signaling that triggered the Cbl and MAPK cascade in concert with downstream synergic over-expression of NFAT and MEF2B, but failed to augment the expression of the nuclear receptor gene family members NR4A1, NR2F1, VDR and MEF2B, that further resulted in impaired apoptotic machinery. Comparison between multiple sclerosis-to-be and first clinical onset of multiple sclerosis operating module networks demonstrated the evolution of altered regulation of nuclear receptor-dependent apoptosis. Our findings demonstrating a silent multiple sclerosis trait that is associated with suppressed expression of the nuclear receptor network and inhibited apoptosis of activated T-cells support the role of these transcription signals in the evolution of the autoimmune processes that operate in the pre-disease stage of multiple sclerosis.

Differential allelic distribution of V-ets erythroblastosis virus E26 oncogene homolog2 (ETS2) functional polymorphisms in different group of patients

V-ets erythroblastosis virus E26 oncogene homolog2 (ETS2), located at chromosome 21 and overexpressed in Down's syndrome (DS), has known cancer regulatory functions. Because leukemia is of common occurrence in DS subjects while solid tumors are rare, we have explored the role of ETS2 functional genetic polymorphisms in this differential oncological development. In silico methods were used for identifying deleterious SNPs, tagged SNPs, and linkage disequilibrium followed by genotyping of 14 SNPs in Indo-Caucasoid individuals (N=668). Significantly different allelic frequencies for rs457705, rs1051420, and rs1051425 were observed in Indian controls (N=149) compared to other ethnic groups. A heterozygous "T" insertion, between chromosomal contig positions 40195541 and 40195542, was observed in DS subjects and their parents. rs461155 showed significant allelic and genotypic association in breast and oral cancer patients. Significantly higher occurrence of G-C haplotype (rs461155-rs1051425) was also observed in these patients compared to DS and leukemic patients. This is the first report on this type of allelic discrimination pattern of ETS2 under different disease conditions. From the data obtained it may be proposed that allelic discrimination of deleterious SNPs in ETS2 may play a regulatory role in the differential development of malignancy in DS subjects.

Complex contributions of Ets2 to craniofacial and thymus phenotypes of trisomic "Down syndrome" mice

Ts65Dn mice have segmental trisomy for orthologs of about half of the genes on human chromosome 21, including Ets2. These mice develop anomalies of the cranial skeleton and thymus that parallel those in Down syndrome. Overexpression of the Ets2 transcription factor gene was posited to be sufficient to produce these craniofacial and thymus deficits in transgenic mice that constitutively overexpress a processed Ets2 transcript under a promiscuous promoter [Sumarsono et al. (1996); Nature 379:534-537; Wolvetang et al. (2003); Hum Mol Genet 12:247-255]. Evaluation of trisomic mice with varying copy numbers of a properly regulated Ets2 gene indicated increased dosage of Ets2 was not sufficient to produce effects on thymus and most of the cranial anomalies seen in Ts65Dn mice. However, mesoderm-derived cranial skeletal elements are significantly more affected in Ts65Dn, Ets2(+/-) mice compared to Ts65Dn littermates suggesting a differential interaction of Ets2-related processes with mesoderm-derived and neural crest-derived formative tissues. Our results support the growing evidence for interactions among multiple genes contributing to developmental perturbations resulting in variation in complex Down syndrome phenotypes.

Insights into the manifestations, outcomes, and mechanisms of leukemogenesis in Down syndrome

Children with Down syndrome (DS) show a spectrum of clinical anomalies, including cognitive impairment, cardiac malformations, and craniofacial dysmorphy. Moreover, hematologists have also noted that these children commonly show macrocytosis, abnormal platelet counts, and an increased incidence of transient myeloproliferative disease (TMD), acute megakaryocytic leukemia (AMKL), and acute lymphoid leukemia (ALL). In this review, we summarize the clinical manifestations and characteristics of these leukemias, provide an update on therapeutic strategies and patient outcomes, and discuss the most recent advances in DS-leukemia research. With the increased knowledge of the way in which trisomy 21 affects hematopoiesis and the specific genetic mutations that are found in DS-associated leukemias, we are well on our way toward designing improved strategies for treating both myeloid and lymphoid malignancies in this high-risk population.

Putative direct and indirect Wnt targets identified through consistent gene expression changes in APC-mutant intestinal adenomas from humans and mice

In order to identify new genes with differential expression in early intestinal tumours, we performed mRNA (messenger ribonucleic acid) expression profiling of 16 human and 63 mouse adenomas. All individuals had germline APC mutations to ensure that tumorigenesis was driven by ‘second hits’ at APC. Using stringent filtering to identify changes consistent between humans and mice, we identified 60 genes up-regulated and 151 down-regulated in tumours. For 22 selected genes—including known Wnt targets—expression differences were confirmed by qRT–PCR (quantitative reverse transcription polymerase chain reaction). Most, but not all, differences were also present in colorectal carcinomas. In situ analysis showed a complex picture. Expression of up-regulated genes in adenomas was usually uniform/diffuse (e.g. ITGA6) or prominent in the tumour core (e.g. LGR5); in normal tissue, these genes were expressed at crypt bases or the transit amplifying zone. Down-regulated genes were often undetectable in adenomas, but in normal tissue were expressed in mesenchyme (e.g. GREM1/2) or differentiated cells towards crypt tops (e.g. SGK1). In silico analysis of TCF4-binding motifs showed that some of our genes were probably direct Wnt targets. Previous studies, mostly focused on human tumours, showed partial overlap with our ‘expression signature’, but 37 genes were unique to our study, including TACSTD2, SEMA3F, HOXA9 and IER3 (up-regulated), and TAGLN, GREM1, GREM2, MAB21L2 and RARRES2 (down-regulated). Combined analysis of our and published human data identified additional genes differentially expressed in adenomas, including decreased BMPs (bone morphogenetic proteins) and increased BUB1/BUB1B. Several of the newly identified, differentially expressed genes represent potential diagnostic or therapeutic targets for intestinal tumours.

Trisomy 21 and Down syndrome: a short review

Even though the molecular mechanisms underlying the Down syndrome (DS) phenotypes remain obscure, the characterization of the genes and conserved non-genic sequences of HSA21 together with large-scale gene expression studies in DS tissues are enhancing our understanding of this complex disorder. Also, mouse models of DS provide invaluable tools to correlate genes or chromosome segments to specific phenotypes. Here we discuss the possible contribution of HSA21 genes to DS and data from global gene expression studies of trisomic samples.

Preparation, crystallization and preliminary X-ray diffraction analysis of the DNA-binding domain of the Ets transcription factor in complex with target DNA

The Ets2 transcription factor is a member of the Ets transcription-factor family. Ets2 plays a role in the malignancy of cancer and in Down's syndrome by regulating the transcription of various genes. The DNA-binding domain of Ets2 (Ets domain; ETSD), which contains residues that are highly conserved among Ets transcription-factor family members, was expressed as a GST-fusion protein. The aggregation of ETSD produced after thrombin cleavage could be prevented by treatment with NDSB-195 (nondetergent sulfobetaine 195). ETSD was crystallized in complex with DNA containing the Ets2 target sequence (GGAA) by the hanging-drop vapour-diffusion method. The best crystals were grown using 25% PEG 3350, 80 mM magnesium acetate, 50 mM sodium cacodylate pH 5.0/5.5 as the reservoir at 293 K. The crystals belonged to space group C2, with unit-cell parameters a = 85.89, b = 95.52, c = 71.89 A, beta = 101.7 degrees and a V(M) value of 3.56 A(3) Da(-1). Diffraction data were collected to a resolution of 3.0 A.

Gene expression pattern in apoptotic QGY-7703 cells induced by homoharringtonine

AIM

To classify the genes responsible for apoptosis in QGY-7703 cells induced by homoharringtonine (HHT).

METHODS

Apoptosis in QGY-7703 cells induced by HHT was demonstrated by DNA fragmentation and morphological observation. cDNA microarray technology was used to detect gene transcription, and the result of microarrays for genes was confirmed by RT-PCR.

RESULTS

Seventy-eight individual mRNA were identified and their transcription levels changed significantly. Those genes, of which 68% were upregulated and 32% were downregulated, were partially related to apoptosis. They were mostly oncogenes, tumor suppressors, enzymes, and kinases.

CONCLUSION

HHT is a potential drug in the treatment of liver cancer. TGF-beta, TNF, FAS, p38MAPK, and p53 apoptosis signaling pathways were activated during apoptosis in QGY-7703 cells. Such inducible genes may play important roles in apoptosis and deserve to be further studied.

Endothelial cells' activation and apoptosis induced by a subset of antibodies against human cytomegalovirus: relevance to the pathogenesis of atherosclerosis

BACKGROUND

Human cytomegalovirus (hCMV) is involved in the pathogenesis of atherosclerosis. We have previously shown in patients with atherosclerosis that antibodies directed against the hCMV-derived proteins US28 and UL122 are able to induce endothelial cell damage and apoptosis of non-stressed endothelial cells through cross-rection with normally expressed surface molecules. Our aim was to dissect the molecular basis of such interaction and to investigate mechanisms linking innate immunity to atherosclerosis.

METHODOLOGY/PRINCIPAL FINDINGS

We analysed the gene expression profiles in endothelial cells stimulated with antibodies affinity-purified against either the UL122 or the US28 peptides using the microarray technology. Microarray results were validated by quantitative PCR and by detection of proteins in the medium. Supernatant of endothelial cells incubated with antibodies was analysed also for the presence of Heat Shock Protein (HSP)60 and was used to assess stimulation of Toll-Like Receptor-4 (TLR4). Antibodies against UL122 and US28 induced the expression of genes encoding for adhesion molecules, chemokines, growth factors and molecules involved in the apoptotis process together with other genes known to be involved in the initiation and progression of the atherosclerotic process. HSP60 was released in the medium of cells incubated with anti-US28 antibodies and was able to engage TLR4.

CONCLUSIONS/SIGNIFICANCE

Antibodies directed against hCMV modulate the expression of genes coding for molecules involved in activation and apoptosis of endothelial cells, processes known to play a pivotal role in the pathogenesis of atherosclerosis. Moreover, endothelial cells exposed to such antibodies express HSP60 on the cell surface and release HSP60 in the medium able to activate TLR4. These data confirm that antibodies directed against hCMV-derived proteins US28 and UL122 purified from patients with coronary artery disease induce endothelial cell damage and support the hypothesis that hCMV infection may play a crucial role in mediating the atherosclerotic process.

Cell-free fetal DNA in amniotic fluid: unique fragmentation signatures in euploid and aneuploid fetuses

BACKGROUND

Circulating cell-free fetal deoxyribonucleic acids (cffDNA) are novel biomarkers with many clinical applications. Amniotic fluid (AF) is a rich source of cffDNA. We investigated the biophysical characteristics of cffDNA in AF, hypothesizing that they would differ from cffDNA in maternal plasma.

METHODS

We obtained 10 mL of fresh AF supernatant from women carrying euploid fetuses (n = 39) and aneuploid fetuses (n = 4). To test the effects of storage and karyotype, samples from euploid fetuses (n = 19) and aneuploid fetuses with trisomies 21 (n = 16), 18 (n = 9), or 13 (n = 3); triploidy (n = 4); or monosomy X (n = 2) were frozen at -80 degrees C. AF cffDNA was characterized by real-time quantitative PCR amplification of glyceraldehyde-3-phosphate dehydrogenase, gel electrophoresis, and analysis of the DNA fragmentation signature.

RESULTS

We observed a significant correlation of concentration with gestational age for fresh AF cffDNA from euploid fetuses (R(2) = 0.77, P <0.0001) but not for frozen cffDNA (P = 0.63). The median amount of cffDNA in frozen euploid samples was significantly lower than in fresh samples (P <0.0001). After adjustment for gestational age, there was a statistically significant decrease in the median amount of cffDNA in frozen aneuploidy samples compared with frozen euploid samples (P = 0.0005). Analysis of the cffDNA size distribution showed different and qualitatively unique patterns for each karyotype.

CONCLUSIONS

Gestational age, karyotype, and sample storage time affect concentrations and fragment size of AF cff DNA. These effects may be attributable to fundamental differences in tissue sources, excretion modes, or kinetic pathways. Characteristic signature patterns for each common aneuploidy offer the possibility of using DNA fragmentation analysis as a means of triaging AF samples.

A conditional model reveals that induction of hepatocyte nuclear factor-1alpha in Hnf1alpha-null mutant beta-cells can activate silenced genes postnatally, whereas overexpression is deleterious

Humans with heterozygous loss-of-function mutations in the hepatocyte nuclear factor-1alpha (HNF1alpha) gene develop beta-cell-deficient diabetes (maturity-onset diabetes of the young type 3), indicating that HNF1alpha gene dosage is critical in beta-cells. However, whether increased HNF1alpha expression might be beneficial or deleterious for beta-cells is unknown. Furthermore, although it is clear that HNF1alpha is required for beta-cell function, it is not known whether this role is cell autonomous or whether there is a restricted developmental time frame for HNF1alpha to elicit gene activation in beta-cells. To address this, we generated a tetracycline-inducible mouse model that transcribes HNF1alpha selectively in beta-cells in either wild-type or Hnf1alpha-null backgrounds. Short-term induction of HNF1alpha in islets from adult Hnf1alpha(-/-) mice that did not express HNF1alpha throughout development resulted in the activation of target genes, indicating that HNF1alpha has beta-cell-autonomous functions that can be rescued postnatally. However, transgenic induction throughout development, which inevitably resulted in supraphysiological levels of HNF1alpha, strikingly caused a severe reduction of cellular proliferation, increased apoptosis, and consequently beta-cell depletion and diabetes. Thus, HNF1alpha is sensitive to both reduced and excessive concentrations in beta-cells. This finding illustrates the paramount importance of using the correct concentration of a beta-cell transcription factor in both gene therapy and artificial differentiation strategies.

ets-2 promotes the activation of a mitochondrial death pathway in Down's syndrome neurons

Down's syndrome (DS) is characterized by mental retardation and development of Alzheimer's disease (AD). Oxidative stress and mitochondrial dysfunction are both related to neurodegeneration in DS. Several genes in chromosome 21 have been linked to neuronal death, including the transcription factor ets-2. Cortical cultures derived from normal and DS fetal brains were used to study the role of ets-2 in DS neuronal degeneration. ets-2 was expressed in normal human cortical neurons (HCNs) and was markedly upregulated by oxidative stress. When overexpressed in normal HCNs, ets-2 induced a stereotyped sequence of apoptotic changes leading to neuronal death. DS HCNs exhibit intracellular oxidative stress and increased apoptosis after the first week in culture (Busciglio and Yankner, 1995). ets-2 levels were increased in DS HCNs, and, between 7 and 14 d in vitro, DS HCNs showed increased bax, cytoplasmic translocation of cytochrome c and apoptosis inducing factor, and active caspases 3 and 7, consistent with activation of an apoptotic mitochondrial death pathway. Degeneration of DS neurons was reduced by dominant-negative ets-2, suggesting that increased ets-2 expression promotes DS neuronal apoptosis. In the human brain, ets-2 expression was found in neurons and astrocytes. Strong ets-2 immunoreactivity was observed in DS/AD and sporadic AD brains associated with degenerative markers such as bax, intracellular Abeta, and hyperphosphorylated tau. Thus, in DS/AD and sporadic AD brains, converging pathological mechanisms leading to chronic oxidative stress and ets-2 upregulation in susceptible neurons may result in increased vulnerability by promoting the activation of a mitochondrial-dependent proapoptotic pathway of cell death.

Advanced microscopic imaging methods to investigate cortical development and the etiology of mental retardation

Studies on human patients and animal models of disease have shown that disruptions in prenatal and early postnatal brain development are a root cause of mental retardation. Since proper brain development is achieved by a strict spatiotemporal control of neurogenesis, cell migration, and patterning of synapses, abnormalities in one or more of these events during prenatal development can lead to cognitive dysfunction after birth. Many of underlying causes of mental retardation must therefore be studied in developing brains. To aid in this research, live imaging using laser scanning microscopy (LSM) has recently allowed neuroscientists to delve deeply into the complex three-dimensional environment of the living brain to record dynamic cellular events over time. This review will highlight recent examples of how LSM is being applied to elucidate both normal and abnormal cortical development.

Essential roles of sphingosine-1-phosphate and platelet-derived growth factor in the maintenance of human embryonic stem cells

Human embryonic stem cells (hESCs) have great potential for use in research and regenerative medicine, but very little is known about the factors that maintain these cells in the pluripotent state. We investigated the role of three major mitogenic agents present in serum--sphingosine-1-phosphate (S1P), lysophosphatidic acid (LPA), and platelet-derived growth factor (PDGF)--in maintaining hESCs. We show here that although LPA does not affect hESC growth or differentiation, coincubation of S1P and PDGF in a serum-free culture medium successfully maintains hESCs in an undifferentiated state. Our studies indicate that signaling pathways activated by tyrosine kinase receptors act synergistically with those downstream from lysophospholipid receptors to maintain hESCs in the undifferentiated state. This study is the first demonstration of a role for lysophospholipid receptor signaling in the maintenance of stem cell pluri-potentiality.

Presence of functional gap junctions in human embryonic stem cells

Gap junctions are intercellular channels that allow both chemical and electrical signaling between two adjacent cells. Gap junction intercellular communication has been implicated in the regulation of various cellular processes, including cell migration, cell proliferation, cell differentiation, and cell apoptosis. This study aimed to determine the presence and functionality of gap junctions in human embryonic stem cells (hESCs). Using reverse transcription--polymerase chain reaction and immunocytochemistry, we demonstrate that human ES cells express two gap junction proteins, connexin 43 and connexin 45. Western blot analysis revealed the presence of three phosphorylated forms (nonphosphorylated [NP], P1, and P2) of connexin 43, NP being prominent. Moreover, scrape loading/dye transfer assay indicates that human ES cells are coupled through functional gap junctions that are inhibited by protein kinase C activation and extracellular signal-regulated kinase inhibition.

Elf5 is essential for early embryogenesis and mammary gland development during pregnancy and lactation

Elf5 is an epithelial-specific ETS factor. Embryos with a null mutation in the Elf5 gene died before embryonic day 7.5, indicating that Elf5 is essential during mouse embryogenesis. Elf5 is also required for proliferation and differentiation of mouse mammary alveolar epithelial cells during pregnancy and lactation. The loss of one functional allele led to complete developmental arrest of the mammary gland in pregnant Elf5 heterozygous mice. A quantitative mRNA expression study and Western blot analysis revealed that decreased expression of Elf5 correlated with the downregulation of milk proteins in Elf5(+/-) mammary glands. Mammary gland transplants into Rag(-/-) mice demonstrated that Elf5(+/-) mammary alveolar buds failed to develop in an Elf5(+/+) mammary fat pad during pregnancy, demonstrating an epithelial cell autonomous defect. Elf5 expression was reduced in Prolactin receptor (Prlr) heterozygous mammary glands, which phenocopy Elf5(+/-) glands, suggesting that Elf5 and Prlr are in the same pathway. Our data demonstrate that Elf5 is essential for developmental processes in the embryo and in the mammary gland during pregnancy.

A major site of expression of the ets transcription factor Elf5 is epithelia of exocrine glands

Elf5 belongs to the ets family of transcription factors and was cloned by homology in the DNA binding domain to the related, epithelial-specific ets factor, Elf3. Elf5 mRNA is expressed highly in normal tissue rich in secretory epithelial cells, including mammary gland, lung, kidney, prostate, salivary gland and stomach. The function of Elf5 and the cell types in which it is expressed remain uncharacterised. The presence of Elf5 mRNA in normal tissues, but absence in cancer tissues, may suggest a role for Elf5 in differentiation and development. We have generated a rabbit antiserum directed against a peptide in the Elf5 DNA-binding domain that is conserved between murine and human sequences. The antiserum specifically detects human and murine Elf5 proteins on western blots and shows specific staining on paraffin-embedded sections obtained from tissues including mammary gland, kidney, salivary gland and stomach. Epithelia from the bladder lining, lung and prostate did not stain for the presence of Elf5, though these organs express Elf5 mRNA. We show for the first time that Elf5 is primarily expressed in epithelial cells and is likely to be an epithelial-specific protein. The antiserum should prove useful in further analysis of the expression and function of Elf5.

The ETS transcription factor ESE-1 transforms MCF-12A human mammary epithelial cells via a novel cytoplasmic mechanism

Several different transcription factors, including estrogen receptor, progesterone receptor, and ETS family members, have been implicated in human breast cancer, indicating that transcription factor-induced alterations in gene expression underlie mammary cell transformation. ESE-1 is an epithelium-specific ETS transcription factor that contains two distinguishing domains, a serine- and aspartic acid-rich (SAR) domain and an AT hook domain. ESE-1 is abundantly expressed in human breast cancer and trans-activates epithelium-specific gene promoters in transient transfection assays. While it has been presumed that ETS factors transform mammary epithelial cells via their nuclear transcriptional functions, here we show (i) that ESE-1 protein is cytoplasmic in human breast cancer cells; (ii) that stably expressed green fluorescent protein-ESE-1 transforms MCF-12A human mammary epithelial cells; and (iii) that the ESE-1 SAR domain, acting in the cytoplasm, is necessary and sufficient to mediate this transformation. Deletion of transcriptional regulatory or nuclear localization domains does not impair ESE-1-mediated transformation, whereas fusing the simian virus 40 T-antigen nuclear localization signal to various ESE-1 constructs, including the SAR domain alone, inhibits their transforming capacity. Finally, we show that the nuclear localization of ESE-1 protein induces apoptosis in nontransformed mammary epithelial cells via a transcription-dependent mechanism. Together, our studies reveal two distinct ESE-1 functions, apoptosis and transformation, where the ESE-1 transcription activation domain contributes to apoptosis and the SAR domain mediates transformation via a novel nonnuclear, nontranscriptional mechanism. These studies not only describe a unique ETS factor transformation mechanism but also establish a new paradigm for cell transformation in general.

Acute myeloid leukemia with complex karyotypes and abnormal chromosome 21: Amplification discloses overexpression of APP, ETS2, and ERG genes

Molecular mechanisms of leukemogenesis have been successfully unraveled by studying genes involved in simple rearrangements including balanced translocations and inversions. In contrast, little is known about genes altered in complex karyotypic abnormalities. We studied acute myeloid leukemia (AML) patients with complex karyotypes and abnormal chromosome 21. High-resolution bacterial artificial chromosome (BAC) array-based comparative genomic hybridization disclosed amplification predominantly in the 25- to 30-megabase (MB) region that harbors the APP gene (26.3 MB) and at position 38.7-39.1 MB that harbors the transcription factors ERG and ETS2. Using oligonucleotide arrays, APP was by far the most overexpressed gene (mean fold change 19.74, P = 0.0003) compared to a control group of AML with normal cytogenetics; ERG and ETS2 also ranked among the most highly expressed chromosome 21 genes. Overexpression of APP and ETS2 correlated with genomic amplification, but high APP expression occurred even in a subset of AML patients with normal cytogenetics (10 of 64, 16%). APP encodes a glycoprotein of unknown function previously implicated in Alzheimer's disease, but not in AML. We hypothesize that APP and the transcription factors ERG and ETS2 are altered by yet unknown molecular mechanisms involved in leukemogenesis. Our results highlight the value of molecularly dissecting leukemic cells with complex karyotypes.

Overexpression of the chromosome 21 transcription factor Ets2 induces neuronal apoptosis

Down syndrome (trisomy 21) neurons display an increased rate of apoptosis in vitro. The genes on chromosome 21 that mediate this increased cell death remain to be elucidated. Here we show that the chromosome 21 transcription factor Ets2, a gene that is overexpressed in Down syndrome, is expressed in neurons, and that moderate overexpression of Ets2 leads to increased apoptosis of primary neuronal cultures from Ets2 tg mice that involves activation of caspase-3. Our data therefore suggest that overexpression of ETS2 may contribute to the increased rate of apoptosis of neurons in Down syndrome.

Ets1 as a marker of malignant potential in gastric carcinoma

AIM: Ets1 proto-oncogene is a transcription factor involved in the activation of several genes of tumor invasion and metastasis. We aimed to determine the relationship between the extent and intensity of Ets1 expression and patients’ clinicopathological factors in gastric carcinoma.

METHODS: Immunohistochemical analysis was performed for gastric tumor paraffin-embedded sections, followed by image analysis.

RESULTS: Ets1 was not expressed in the normal gastric epithelium and its surrounding cells. The percentage of Ets1 expressing cells detected increased significantly in both epithelial tumor and stromal cells from high T classification, lymph node metastasis positive, clinical advanced-stage groups (P < 0.001). The level of Ets1 staining in epithelial tumor cells also reflected the degree of cell differentiation. The percentage of epithelial and stromal cells expressing Ets1 was significantly correlated with the presence of lymph node metastasis (P = 0.014 and P < 0.001 respectively). Ets1 expression was not observed in tissue samples from patients with benign gastric ulcers.

CONCLUSION: Ets1 protein expression in epithelial tumor cells reflects the degree of differentiation, and the percentage of Ets1 positive tumor and stromal cells correlates with lymph node metastasis. Thus Ets1 is a valuable marker of malignant potential in terms of invasiveness and metastasis of gastric carcinoma. It is also possible that inhibition of Ets1 is a potential avenue for therapy in gastric cancer.

The chromosome 21 transcription factor ETS2 transactivates the beta-APP promoter: implications for Down syndrome

The gene that codes for beta-amyloid precursor protein (beta-APP), a protein centrally involved in senile plaque formation in Down syndrome (DS) and Alzheimer's disease (AD), is located on chromosome 21. In DS beta-APP expression is three- to fourfold higher than what is expected from the 1.5-fold increased gene load, suggesting that other genes on chromosome 21 directly or indirectly can further up-regulate beta-APP. Here we show that the chromosome 21 transcription factor ETS2 transactivates the beta-APP gene via specific Ets binding sites in the beta-APP promoter and, in this respect, cooperates with the transcription factor complex AP1. We further show that brains and primary neuronal cultures from Ets2 transgenic mice, as well as 3T3 fibroblasts that overexpress ETS2, display molecular abnormalities also seen in DS, such as elevated expression of beta-APP protein, an increase in presenilin-1 and increased beta-amyloid production. We conclude that ETS2 is a transcriptional regulator of beta-APP and that overexpression of ETS2 in DS may play a role in the pathogenesis of the brain abnormalities in DS and possibly AD.