Isolation of a cDNA encoding the adenovirus E1A enhancer binding protein: a new human member of the ets oncogene family

ETV4 facilitates angiogenesis in hepatocellular carcinoma by upregulating MMP14 expression

Abnormal vascularization plays a crucial role in cell proliferation, tumor invasion and metastasis of hepatocellular carcinoma (HCC). It has been reported that ETV4 functions as an oncogenic gene in driving the carcinogenesis and progression, and promoting invasion and metastasis of HCC. However, the function of ETV4 on angiogenesis in HCC remains unclear. In the current study, immunohistochemistry showed that knockdown of ETV4 reduced angiogenesis in HCC xenograft tumor tissues. In vitro, tube formation assay verified that ETV4 expression promoted angiogenesis through simulating the angiogenic environment in HCC cells. Transcriptome sequencing indicated that MMP14 was one of the differentially expressed genes enriched in angiogenesis process. Subsequently, it was confirmed that MMP14 was regulated by ETV4 at the transcription level in HCC cells, clinical tissue samples and online databases. Further, we demonstrated that MMP14 induced angiogenesis in ETV4-mediated HCC microenvironment. Collectively, this research further reveals the biological mechanism of ETV4 in promoting the migration and invasion of HCC, and provides novel mechanistic insights and strategic guidance for anti-angiogenic therapy in HCC.

ETV4 plays a role on the primary events during the adenoma-adenocarcinoma progression in colorectal cancer

BACKGROUND

Colorectal cancer (CRC) is one of the most common cancers worldwide; it is the fourth leading cause of death in the world and the third in Brazil. Mutations in the APC, DCC, KRAS and TP53 genes have been associated with the progression of sporadic CRC, occurring at defined pathological stages of the tumor progression and consequently modulating several genes in the corresponding signaling pathways. Therefore, the identification of gene signatures that occur at each stage during the CRC progression is critical and can present an impact on the diagnosis and prognosis of the patient. In this study, our main goal was to determine these signatures, by evaluating the gene expression of paired colorectal adenoma and adenocarcinoma samples to identify novel genetic markers in association to the adenoma-adenocarcinoma stage transition.

METHODS

Ten paired adenoma and adenocarcinoma colorectal samples were subjected to microarray gene expression analysis. In addition, mutations in APC, KRAS and TP53 genes were investigated by DNA sequencing in paired samples of adenoma, adenocarcinoma, normal tissue, and peripheral blood from ten patients.

RESULTS

Gene expression analysis revealed a signature of 689 differentially expressed genes (DEG) (fold-change> 2, p< 0.05), between the adenoma and adenocarcinoma paired samples analyzed. Gene pathway analysis using the 689 DEG identified important cancer pathways such as remodeling of the extracellular matrix and epithelial-mesenchymal transition. Among these DEG, the ETV4 stood out as one of the most expressed in the adenocarcinoma samples, further confirmed in the adenocarcinoma set of samples from the TCGA database. Subsequent in vitro siRNA assays against ETV4 resulted in the decrease of cell proliferation, colony formation and cell migration in the HT29 and SW480 colorectal cell lines. DNA sequencing analysis revealed KRAS and TP53 gene pathogenic mutations, exclusively in the adenocarcinomas samples.

CONCLUSION

Our study identified a set of genes with high potential to be used as biomarkers in CRC, with a special emphasis on the ETV4 gene, which demonstrated involvement in proliferation and migration.

Methylation Patterns of the HTR2A Associate With Relapse-Related Behaviors in Cocaine-Dependent Participants

Relapse during abstinence in cocaine use disorder (CUD) is often hastened by high impulsivity (predisposition toward rapid unplanned reactions to stimuli without regard to negative consequences) and high cue reactivity (e.g., attentional bias towards drug reward stimuli). A deeper understanding of the degree to which individual biological differences predict or promote problematic behaviors may afford opportunities for clinical refinement and optimization of CUD diagnostics and/or therapies. Preclinical evidence implicates serotonin (5-HT) neurotransmission through the 5-HT_2A receptor (5-HT_2AR) as a driver of individual differences in these relapse-related behaviors. Regulation of 5-HT_2AR function occurs through many mechanisms, including DNA methylation of the HTR2A gene, an epigenetic modification linked with the memory of gene-environment interactions. In the present study, we tested the hypothesis that methylation of the HTR2A may associate with relapse-related behavioral vulnerability in cocaine-dependent participants versus healthy controls. Impulsivity was assessed by self-report (Barratt Impulsiveness Scale; BIS-11) and the delay discounting task, while levels of cue reactivity were determined by performance in the cocaine-word Stroop task. Genomic DNA was extracted from lymphocytes and the bisulfite-treated DNA was subjected to pyrosequencing to determine degree of methylation at four cytosine residues of the HTR2A promoter (-1439, -1420, -1224, -253). We found that the percent methylation at site -1224 after correction for age trended towards a positive correlation with total BIS-11 scores in cocaine users, but not healthy controls. Percent methylation at site -1420 negatively correlated with rates of delay discounting in healthy controls, but not cocaine users. Lastly, the percent methylation at site -253 positively correlated with attentional bias toward cocaine-associated cues. DNA methylation at these cytosine residues of the HTR2A promoter may be differentially associated with impulsivity or cocaine-associated environmental cues. Taken together, these data suggest that methylation of the HTR2A may contribute to individual differences in relapse-related behaviors in CUD.

Pea3 transcription factor promotes neurite outgrowth

Pea3 subfamily of E–twenty six transcription factors consist of three major -exhibit branching morphogenesis, the function of Pea3 family in nervous system development and regeneration is only beginning to unfold. In this study, we provide evidence that Pea3 can directs neurite extension and axonal outgrowth in different model systems, and that Serine 90 is important for this function. We have also identified neurofilament-L and neurofilament-M as two putative novel targets for Pea3.

Impaired c-src activation and motility defects in PEA3-null fibroblasts

Null mutations in the pea3 allele compromise the capacity of mammary tumors to metastasize in MMTV-Neu/ErbB2/HER2 transgenic mice, indicating a motility defect in PEA3-null cells. Cellular and biochemical analyses of established PEA3-null fibroblasts show impaired motility and aberrant localization of adhesion proteins in spreading cells. Our results show that PEA3-/- cells express normal levels of key adhesion components, but that spreading PEA3-null cells fail to activate c-src and to downregulate phospho-FAK(Y397), suggesting that focal adhesion signaling is impaired. Supporting this, biochemical analysis revealed that adhesion complex-associated proteins such as p130Cas failed to undergo tyrosine phosphorylation and dissociated from the adhesion complex with delayed kinetics. Overall our data show that the motility defects observed in PEA3-null cells are due to altered adhesion signaling.

E1A expression might be controlled by miR-214 in cells with low adenovirus productivity

In this study, we explored the differences in the human adenovirus type 5 (Ad5) production efficiencies of various cell types. The rate of virus production was higher in several cell lines, such as HeLa cells, than in Saos-2 cells. The expression level of the coxsackie and adenovirus receptor (CAR) protein, an adenovirus receptor, was very similar among these cell lines. Although no significant difference in the expression of early region 1A (E1A) mRNA was detected, the amount of E1A protein in the Saos-2 cells was markedly lower than that in HeLa cells. Proteasome inhibitor treatment did not rescue the quantity of E1A in the Saos-2 cells, suggesting that their decreased E1A protein expression is not due to protein decay. To examine the different expression of E1A protein, we employed a bioinformatics approach to identify miRNA that target the 3'-untranslated region (3'-UTR) of E1A mRNA and identified miR-214 as a highly promising candidate. In Saos-2 cells, which have abundant levels of endogenous miR-214, the expression of luciferase was dramatically repressed, when the reporter gene was fused with the 3'-UTR of E1A mRNA including an miR-214 binding site. On the other hand, the activity from the same reporter was unchanged in HeLa cells, which display low-level miR-214 expression. Finally, we confirmed that the knockdown of the miR-214 upregulated the productive efficiency of the virus. These findings indicate that cellular miR-214 is capable of inhibiting adenovirus replication by regulating the translation of E1A protein.

ETV1, 4 and 5: an oncogenic subfamily of ETS transcription factors

The homologous ETV1, ETV4 and ETV5 proteins form the PEA3 subfamily of ETS transcription factors. In Ewing tumors, chromosomal translocations affecting ETV1 or ETV4 are an underlying cause of carcinogenesis. Likewise, chromosomal rearrangements of the ETV1, ETV4 or ETV5 gene occur in prostate tumors and are thought to be one of the major driving forces in the genesis of prostate cancer. In addition, these three ETS proteins are implicated in melanomas, breast and other types of cancer. Complex posttranslational modifications govern the activity of PEA3 factors, which can promote cell proliferation, motility and invasion. Here, we review evidence for a role of ETV1, 4 and 5 as oncoproteins and describe modes of their action. Modulation of their activation or interaction with cofactors as well as inhibiting crucial target gene products may ultimately be exploited to treat various cancers that are dependent on the PEA3 group of ETS transcription factors.

Pea3 transcription factors and wnt1-induced mouse mammary neoplasia

The role of the PEA3 subfamily of Ets transcription factors in breast neoplasia is controversial. Although overexpression of PEA3 (E1AF/ETV4), and of the related factors ERM (ETV5) and ER81 (ETV1), have been observed in human and mouse breast tumors, PEA3 factors have also been ascribed a tumor suppressor function. Here, we utilized the MMTV/Wnt1 mouse strain to further interrogate the role of PEA3 transcription factors in mammary tumorigenesis based on our previous observation that Pea3 is highly expressed in MMTV/Wnt1 mammary tumors. Pea3 expression in mouse mammary tissues was visualized using a Pea3^NLSlacZ reporter strain. In normal mammary glands, Pea3 expression is predominantly confined to myoepithelial cells. Wnt1 transgene expression induced marked amplification of this cell compartment in nontumorous mammary glands, accompanied by an apparent increase in Pea3 expression. The pattern of Pea3 expression in MMTV/Wnt1 mammary glands recapitulated the cellular profile of activated β-catenin/TCF signaling, which was visualized using both β-catenin immunohistochemistry and the β-catenin/TCF-responsive reporter Axin2^NLSlacZ. To test the requirement for PEA3 factors in Wnt1-induced tumorigenesis, we employed a mammary-targeted dominant negative PEA3 transgene, ΔNPEA3En. Expression of ΔNPEA3En delayed early-onset tumor formation in MMTV/Wnt1 virgin females (P = 0.03), suggesting a requirement for PEA3 factor function for Wnt1-driven tumor formation. Consistent with this observation, expression of the ΔNPEA3En transgene was profoundly reduced in mammary tumors compared to nontumorous mammary glands from bigenic MMTV/Wnt1, MMTV/ΔNPEA3En mice (P = 0.01). Our data provide the first description of Wnt1-mediated expansion of the Pea3-expressing myoepithelial compartment in nontumorous mammary glands. Consistent with this observation, mammary myoepithelium was selectively responsive to Wnt1. Together these data suggest the MMTV/Wnt1 strain as a potential model of basal breast cancer. Furthermore, this study provides evidence for a protumorigenic role of PEA3 factors in breast neoplasia, and supports targeting the PEA3 transcription factor family in breast cancer.

The Pea3 Ets transcription factor regulates differentiation of multipotent progenitor cells during mammary gland development

The Pea3 Ets transcription factor is overexpressed in breast tumors suggesting that it plays a role in mammary oncogenesis. However, the normal biological function of Pea3 in the mammary gland is not known. Here we report that Pea3 was expressed in the epithelium of the mouse mammary anlagen commensurate with their genesis, and at later times in the nipple and mammary ducts of female embryos. In adult mice Pea3 transcripts peaked at the onset of puberty and early pregnancy, times of active epithelial cell proliferation and differentiation. Pea3 was expressed in all progenitor cap cells and rare body cells of terminal end buds, and in the myoepithelial cells of ducts and alveoli. Analyses of the mammary glands of Pea3-null mice during puberty revealed an increased number of terminal end buds and an increased fraction of proliferating progenitor cells within these structures compared to their wild type littermates. Tissue transplant experiments demonstrated that these phenotypes were intrinsic to the Pea3-null mammary epithelium. During pregnancy, mammary glands isolated from Pea3-null females had impaired alveolar development as revealed by a decreased fraction of alveolar structures. We performed in vitro colony forming assays of mammary epithelial cells and discovered that loss of Pea3 altered the distribution of specific multipotent progenitor cells. Double-immunofluorescence confirmed that multipotential progenitors co-expressing markers of the myoepithelial and luminal epithelial lineage were amplified in the mammary glands of Pea3-null mice by comparison to their wild type counterparts. We propose that Pea3 functions in multipotential progenitors to regulate their lineage-specific differentiation potential.

Repression of E1AF transcriptional activity by sumoylation and PIASy

E1AF is a member of the Ets transcriptional factor family, and it plays a crucial role in tumor metastasis. However, the molecular mechanisms regulating its activity are not well characterized. In this study, we show that E1AF is sumoylated at four lysine residues, both in vivo and in vitro. Replacement of these lysines by arginine enhanced the transcriptional activity of E1AF, suggesting that sumoylation negatively regulates E1AF activity. We further demonstrated that PIASy enhanced sumoylation of E1AF as a specific SUMO-E3 ligase. In addition, PIASy repressed the transcriptional activity of both the wild-type and sumoylation defective mutants. However, the C342A mutant of PIASy, which abrogates SUMO-E3 ligase activity, had a significantly decreased ability to repress E1AF activity. Taken together, our results indicate that PIASy negatively regulates E1AF-mediated transcription by both E1AF sumoylation in a dependent and independent fashion.

Adenovirus E1A negatively regulates E1AF, an ets family of the protein

E1AF was first identified as a transcription factor that binds to enhancer motifs of the adenovirus E1A gene and is thought to be a human homologue of mouse PEA3, one of the ets oncoprotein families. Here we show the effect of E1A on the gene expression and function of E1AF. E1A repressed the activity of E1AF promoter, and the N-terminal region of E1A, which is involved in the oncogenic activity of E1A, was essential for this repression. The ability as a transcription factor of E1AF, as well as those of the other PEA3 subfamily members ER81 and ERM, was also repressed by E1A via the same oncogenic domain. Furthermore, E1AF repressed the transformation activity of E1A cooperating with E1B, whereas the other ets family Ets-1 enhanced this activity. These results suggest that E1AF is one of the targets of E1A.

The Ets transcription factors of the PEA3 group: transcriptional regulators in metastasis

The PEA3 group is composed of three highly conserved Ets transcription factors: Erm, Er81, and Pea3. These proteins regulate transcription of multiple genes, and their transactivating potential is affected by post-translational modifications. Among their target genes are several matrix metalloproteases (MMPs), which are enzymes degrading the extracellular matrix during normal remodelling events and cancer metastasis. In fact, PEA3-group genes are often over-expressed in different types of cancers that also over-express these MMPs and display a disseminating phenotype. Experimental regulation of the synthesis of PEA3 group members influences the metastatic process. This suggests that these factors play a key role in metastasis.

Genomic structure and promoter activity of the E1AF gene, a member of the ETS oncogene family

E1AF is a member of the ETS oncogene family and is thought to be a human homologue of mouse PEA3. We have isolated a genomic clone of E1AF and analyzed the promoter activity of its 5'-flanking region. We identified a variation in exon 1, which depends on the cell type. There was no typical TATA box in the 5'-flanking region, but putative binding sites of a number of transcription factors including PEA3 as well as CAAT boxes were seen. A luciferase reporter assay indicated that the 5'-flanking region possesses promoter activity. Northern blot studies demonstrated significant expression of the E1AF gene in restricted tissues such as the pituitary gland, placenta, and fetal kidney. Moreover, the E1AF promoter was activated by E1AF itself and estrogen receptor. These findings suggest that E1AF is a housekeeping gene, whose expression is controlled in specific tissues.

E1A-F is overexpressed early in human colorectal neoplasia and associated with cyclooxygenase-2 and matrix metalloproteinase-7

Studies suggest the expression of cyclooxygenase-2 (COX-2) and matrilysin (MMP-7) increase in the early stages of colorectal carcinogenesis, however their interaction with other molecular markers is poorly understood. Results from cell line studies and mouse models suggest polyomavirus enhancer activator 3 (PEA3) may play a role in the activation of COX-2 and MMP-7 promoters. However, the role of E1A-F, the human homolog of murine PEA3, in colorectal cancer (CRC) development has not been elucidated. In this study, we used real-time reverse transcription (RT)-polymerase chain reaction (PCR) to measure the levels of E1A-F, COX-2, and MMP-7 in matched normal mucosa, adenomas, and/or carcinomas from 128 patients. Our results demonstrate significant overexpression of E1A-F and MMP-7 in adenomas and E1A-F, COX-2, and MMP-7 in carcinomas. In carcinomas, E1A-F expression was significantly associated with both COX-2 and MMP-7 overexpression. These results suggest E1A-F is overexpressed in early stages of human CRC development and may be an important factor in the overexpression of COX-2 and MMP-7.

Prognostic value of ERM gene expression in human primary breast cancers

We measured the expression of ERM gene, a nuclear transcription factor belonging to the ets family, in a series of 364 unselected primary breast cancers from patients who underwent locoregional surgery in the Centre Oscar Lambret between May 1989 and December 1991. The expression of ERM was quantified with a real-time one-step reverse transcription-PCR assay based on the 5'-nuclease activity of the TaqDNA polymerase and with an Abi Prism 7700 Sequence Detector System (Applied Biosystems, Courtaboeuf, France). ERM was positively correlated (Spearman test) to epidermal growth factor receptor (EGFR; P < 0.001, r = 0.296) and to histoprognostic grading (P = 0.044, r = 0.112), whereas it was negatively correlated to estradiol receptors (P = 0.019, r = -0.124), HER3 (c-erbB-3; P = 0.01, r = -0.135), and HER4 (c-erbB-4; P = 0.003, r = -0.154). Using the chi2 test, a positive relationship was found between the expression of ERM and EGFR (chi2 = 7.795, P = 0.007). In overall survival studies, Cox univariate analyses demonstrated a prognostic value of ERM (P = 0.006; risk ratio, 2.95) besides the classical prognostic factors histoprognostic grading, node involvement, tumor size, estradiol receptors, progesterone receptors, EGFR, HER3, and HER4. In multivariate analyses, ERM preserved its prognostic value (P = 0.004; risk ratio, 3.779) together with histoprognostic grading, tumor size, estradiol receptors, and progesterone receptors. In relapse-free survival studies, univariate analyses demonstrated that histoprognostic grading, node involvement, tumor size, and HER4 were prognostic factors. These parameters, except histoprognostic grading, retained their prognostic value in multivariate analyses. This study demonstrates for the first time that ERM gene expression is an independent adverse prognostic factor for overall survival in breast cancer patients.

E1AF degradation by a ubiquitin-proteasome pathway

E1AF is a member of the ETS family of transcription factors. In mammary tumors, overexpression of E1AF is associated with tumorigenesis, but E1AF protein has hardly been detected and its degradation mechanism is not yet clear. Here we show that E1AF protein is stabilized by treatment with the 26S protease inhibitor MG132. We found that E1AF was modified by ubiquitin through the C-terminal region and ubiquitinated E1AF aggregated in nuclear dots, and that the inhibition of proteasome-activated transcription from E1AF target promoters. These results suggest that E1AF is degraded via the ubiquitin-proteasome pathway, which has some effect on E1AF function.

Pea3 Transcription Factor Cooperates with USF-1 in Regulation of the Murine bax Transcription without Binding to an Ets-binding Site

The Pea3 transcription factor (which belongs to the PEA3 group) from the Ets family has been shown to be involved in mammary embryogenesis and oncogenesis. However, except for proteinases, only few of its target genes have been reported. In the present report, we identified bax as a Pea3 up-regulated gene. We provide evidence of this regulation by using Pea3 overexpression and Pea3 silencing in a mammary cell line. Both Pea3 and Erm, another member of the PEA3 group, are able to transactivate bax promoter fragments. Although the minimal Pea3-regulated bax promoter does not contain an Ets-binding site, two functional upstream stimulatory factor-regulated E boxes are present. We further demonstrate the ability of Pea3 and USF-1 to cooperate for the transactivation of the bax promoter, mutation of the E boxes dramatically reducing the Pea3 transactivation potential. Although Pea3 did not directly bind to the minimal bax promoter, we provide evidence that USF-1 could form a ternary complex with Pea3 and DNA. Taken together, our results suggest that Pea3 may regulate bax transcription via the interaction with USF-1 but without binding to DNA.

The clinical role of the PEA3 transcription factor in ovarian and breast carcinoma in effusions

Ets transcription factors play a central role in invasion and metastasis through regulation of synthesis of proteolytic enzymes and angiogenic molecules. The objective of this study was to investigate the role of PEA3 in tumor progression of ovarian and breast carcinoma metastatic to effusions, and to evaluate the expression of Ets-2 and Erg in ovarian carcinoma. Ovarian (83 malignant effusions, 102 corresponding solid lesions) and breast (33 malignant effusions, 40 corresponding solid lesions) carcinomas were evaluated for expression of PEA3 using mRNA in situ Hybridization (ISH). Expression of Ets-2 and Erg mRNA was analyzed in 50 ovarian carcinoma effusions using the same method. PEA3 mRNA expression was comparable at all sites in ovarian carcinoma (44 out of 83; 53% of effusions, 48 out of 102; 47% of solid tumors). PEA3 mRNA expression in effusions correlated with mRNA expression of the previously studied alphav (P = 0.022), alpha6 (P < 0.001) and beta1 (P < 0.001) integrin subunits, the matrix metalloproteinase (MMP) inducer EMMPRIN (P = 0.015) and interleukin-8 (IL-8) (P = 0.033). Erg and Ets-2 mRNA was expressed in 15 out of 50 (30%) and 18 out of 50 (36%) effusions, respectively, and co-localized with PEA3 (P = 0.017 for Erg, P = 0.004 for Ets-2). In breast carcinoma, PEA3 expression was seen in 19/40 (48%) of solid lesions, with a significant upregulation in corresponding effusions compared to primary tumors (24 out of 33; 73%, P = 0.038). PEA3 mRNA expression in effusions obtained prior to the institution of chemotherapy predicted significantly shorter overall survival in univariate analysis (24 vs 37 months, P = 0.03), with a similar trend for Erg (13 vs 30 months, P = 0.1). In conclusion, PEA3 is expressed at all anatomic sites in serous ovarian cancer and co-localizes with Erg, Ets-2 and several metastasis-associated molecules. PEA3 mRNA expression is a novel marker for tumor progression to malignant effusion in breast carcinoma, and predicts poor outcome in effusions sampled prior to therapeutic intervention in ovarian carcinoma. These findings support a biological role for Ets transcription factors in these malignancies and suggests that they may be targets for therapeutic intervention.

E1AF/PEA3 reduces the invasiveness of SiHa cervical cancer cells by activating serine proteinase inhibitor squamous cell carcinoma antigen

E1AF/PEA3, a member of the Ets family of transcription factors, is associated with the malignant characteristics of cancer cells. The initial aim of our study was to test whether the invasiveness of SiHa cervical cancer cells could be diminished by transfection with antisense E1AF. Using an in vitro invasion assay in which cells penetrate a layer of Matrigel, we found that this was not the case; indeed, the invasiveness of the transfectants was enhanced. To better understand the mechanism of this enhancement, we used the cDNA microarray technique to search for genes whose expression was altered in the antisense E1AF-transfected SiHa cells. Among several genes affected, we found that expression of squamous cell carcinoma antigen (SCCA), a member of the ovalbumin serine proteinase inhibitor family, was significantly reduced. Forced expression of E1AF enabled activation of SCCA expression, and Luciferase reporter assays revealed that E1AF activates the SCCA promoter. Introduction of antisense SCCA into SiHa cells inhibited production of SCCA protein and markedly increased the invasiveness of the cells. Taken together, these results suggest that E1AF suppresses the invasiveness of SiHa cervical cancer cells through transcriptional activation of the SCCA serine proteinase inhibitor gene.

Association of ets-related transcriptional factor E1AF expression with tumour progression and overexpression of MMP-1 and matrilysin in human colorectal cancer

Expression of E1AF/PEA3 (ETV4), an ets family transcription factor, has been implicated in the invasive potential of several cancer cell lines through induction of matrix metalloproteinase (MMP) expression. The aim of this study was to examine E1AF mRNA expression and to determine whether it is correlated with progression of, and/or MMP expression in, human colorectal cancer. Using the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR), 100 colorectal cancer tissues were analysed for E1AF mRNA expression. Expression of ER81 (ETV1) and ERM (ETV5), the other two members of the PEA3 subfamily, and Ets-1 and Ets-2 was also analysed. The results were correlated with clinicopathological characteristics and MMP expression. Immunohistochemical analysis and an in vitro invasion assay were also performed. E1AF mRNA expression was detected in 62% of the 100 colorectal cancer tissues, but was undetectable or only faintly detected in adjacent non-tumour tissues. E1AF mRNA was detected in all of the ten liver metastases from colorectal cancers. E1AF expression correlated significantly with depth of invasion, lymphatic and venous invasion, lymph node and distant metastasis, advance in pathological tumour-node-metastasis stage, and recurrence. Patients with E1AF-positive tumours had significantly shorter overall and disease-free survival periods than did those with E1AF-negative tumours (p < 0.0001 and p < 0.0001, respectively). E1AF expression retained its significant predictive value for overall and disease-free survival in multivariate analysis that included conventional clinicopathological factors (p = 0.0066 and p = 0.0109, respectively). Among the MMPs analysed, expression of MMP-1 and matrilysin correlated significantly with E1AF expression. In contrast, expression of ER81 and ERM did not correlate with clinicopathological characteristics or the expression of these MMPs. Immunohistochemical expression of E1AF was predominantly observed at the invasive front, where the expression of MMP-1 and matrilysin and nuclear beta-catenin expression were often co-localized. Antisense E1AF-transfected HT-29 colon cancer cells expressed reduced levels of MMP-1 and matrilysin and were less invasive in vitro than neo-transfected HT-29 cells. The results of this study suggest that E1AF, the expression of which is closely correlated with the expression of MMP-1 and matrilysin, plays a key role in the progression of colorectal cancer.

Function of PEA3 Ets transcription factors in mammary gland development and oncogenesis

The Ets gene families of mice and man currently comprise 27 genes that encode sequence-specific transcription factors. Ets proteins share an approximately 85 amino acid structurally conserved ETS DNA binding domain. Genetic analyses in model organisms suggest roles for Ets proteins in embryonic development and various adult physiological processes. Chromosomal translocations involving several ETS genes are associated with Ewing's sarcomas and leukemias, whereas the overexpression of some ETS genes is linked with numerous malignancies, including breast cancer. Indeed PEA3, ETS-1, PDEF, and ELF-3 transcripts have all been reported to be elevated in human breast tumors. Some of the ETS genes that are overexpressed in human breast tumors are also overexpressed in mouse models of this disease. Notably, pea3, as well as its close paralogs er81 and erm, which comprise the pea3 subfamily of ets genes, are coordinately overexpressed in mouse mammary tumors. Genetic analyses in mice reveal required roles for one or more of the PEA3 subfamily Ets proteins in the initiation and progression of mouse mammary tumors. The pea3 subfamily genes are normally expressed in the primitive epithelium of mouse mammary buds during embryogenesis, and these three genes are expressed in epithelial progenitor cells during postnatal mammary gland development. Loss-of-function mutations in the mouse pea3 gene results in increased numbers of terminal end buds and an increased fraction of proliferating cells in these structures, suggesting a role for PEA3 in progenitor cell renewal or terminal differentiation. Taken together these observations suggest that the PEA3 subfamily proteins play key regulatory roles in both mammary gland development and oncogenesis.

ERM transactivation is up-regulated by the repression of DNA binding after the PKA phosphorylation of a consensus site at the edge of the ETS domain

The final step of the transduction pathway is the activation of gene transcription, which is driven by kinase cascades leading to changes in the activity of many transcription factors. Among these latter, PEA3/E1AF, ER81/ETV1, and ERM, members of the well conserved PEA3 group from the Ets family are involved in these processes. We show here that protein kinase A (PKA) increases the transcriptional activity of human ERM and human ETV1, through a Ser residue situated at the edge of the ETS DNA-binding domain. PKA phosphorylation does not directly affect the ERM transactivation domains but does affect DNA binding activity. Unphosphorylated wild-type ERM bound DNA avidly, whereas after PKA phosphorylation it did so very weakly. Interestingly, S367A mutation significantly reduced the ERM-mediated transcription in the presence of the kinase, and the DNA binding of this mutant, although similar to that of unphosphorylated wild-type protein, was insensitive to PKA treatment. Mutations, which may mimic a phosphorylated serine, converted ERM from an efficient DNA-binding protein to a poor DNA binding one, with inefficiency of PKA phosphorylation. The present data clearly demonstrate a close correlation between the capacity of PKA to increase the transactivation of ERM and the drastic down-regulation of the binding of the ETS domain to the targeted DNA. What we thus demonstrate here is a relatively rare transcription activation mechanism through a decrease in DNA binding, probably by the shift of a non-active form of an Ets protein to a PKA-phosphorylated active one, which should be in a conformation permitting a transactivation domain to be active.

Clinical significance of PEA3 in human breast cancer

BACKGROUND

Recently, PEA3 has been reported to suppress HER-2/neu overexpression by promoter activity and thereby inhibit tumorigenesis of breast cancer both in vitro and in vivo.

METHODS

The expression of PEA3 and the clinicopathologic features of 89 patients with breast cancer were investigated. The expression of PEA3 was immunohistochemically detected in 42 (47.2%) of 89 patients.

RESULTS

The correlation between the expression of PEA3 and the clinicopathologic features were nil with regard to lymph node metastasis, hormone receptor, blood vessel invasion, and lymphatic vessel invasion. The disease-free survival rate was shorter for the PEA3-negative groups than for the PEA3-positive ones, but with no statistically significant difference. The overall survival rate after surgical resection in patients who were PEA3-positive vs PEA3-negative was 100% vs 87.2%, respectively, at 3 years and 89.8% vs 72.7%, respectively, at 6 years (P =.0472).

CONCLUSIONS

The expression of PEA3 in breast cancer might therefore be a novel prognostic factor.

The pea3 subfamily ets genes are required for HER2/Neu-mediated mammary oncogenesis

BACKGROUND

The PEA3 Ets transcription factor is overexpressed in the vast majority of human breast tumors and in nearly all of those of the HER2/Neu-positive subclass. PEA3 is also overexpressed in various transgenic mouse models of this disease. Whether PEA3 plays an essential role in HER2/Neu-mediated oncogenesis has heretofore not been addressed.

RESULTS

Here, we report that each of the three highly related ets genes of the pea3 subfamily (pea3, er81, and erm) were coordinately overexpressed in mammary tumors of MMTV-neu transgenic mice. Other ets genes normally expressed in the mammary gland were not upregulated in these tumors. Expression of a dominant-negative pea3 transgene under the control of the MMTV promoter in mammary epithelial cells of MMTV-neu transgenic mice dramatically delayed the onset of mammary tumors and reduced the number and size of such tumors in individual mice. Those tumors that arose in bitransgenic mice expressed the MMTV-neu transgene, but not the MMTV-dominant-negative pea3 transgene.

CONCLUSIONS

These findings imply that one or more of the PEA3 subfamily Ets proteins or other Ets proteins with related DNA binding specificity play an essential role in Neu-mediated mammary oncogenesis. Hence, agents that inhibit the expression or activity of the PEA3 subfamily proteins may prove efficacious in the treatment of breast cancer.

Expression of E1AF/PEA3, an Ets-related transcription factor in human non-small-cell lung cancers: its relevance in cell motility and invasion

Cell invasion and metastasis characterize the malignant potential of non-small-cell lung cancers (NSCLCs). We have previously reported that E1AF, a member of the Ets-related transcription factor family, confers invasive phenotype on breast cancer and oral squamous-cell carcinoma cell lines. In our study, we analyzed the E1AF expression in cell lines and resected tumors of NSCLCs by Northern blot and in situ hybridization analyses and found that 15 of 17 cell lines and 12 of 19 tumors expressed E1AF mRNA while normal lung tissue and concomitant normal cells within tumors did not. To examine the biologic importance of E1AF in NSCLCs, we introduced the E1AF gene into VMRC-LCD and NCI-H226, NSCLC cell lines lacking E1AF expression, and examined cell motility and invasion activities. E1AF-transfected VMRC-LCD cells showed increased cell motility that was 2-fold that of parental and vector-transfected control cells (p < 0.01), and both cell motility and invasion were increased 1.6-fold in NCI-H226 (p < 0.01). Furthermore, hepatocyte growth factor (HGF), which is one of the most effective cell-scattering factors, stimulated the motile and invasive activities in E1AF-transfected VMRC-LCD and NCI-H226 cells but not in their parental or vector-transfected control cells. Ets-1 mRNA expression was found in E1AF-transfected VMRC-LCD cells but not in parental or vector-transfected cells. HGF further induced expression of the Ets-1 and urokinase-type plasminogen activator (uPA) genes specifically in E1AF-transfected cells. These findings suggest that E1AF plays a substantial role in the cell motility and invasion of NSCLCs.

Tight transcriptional control of the ETS domain factors Erm and Pea3 by Fgf signaling during early zebrafish development

Several molecules of the Fibroblast growth factor family have been implicated in the development of the vertebrate brain, but the effectors of these molecules remain largely unknown. Here we study Erm and Pea3, two ETS domain transcription factors, and show that their expression correlates closely with the domains of fgf8 and fgf3 expression. In situ hybridization analysis in wild-type and acerebellar (ace) mutant embryos defective for fgf8 demonstrates a requirement of Fgf8 for normal expression levels of erm and pea3 transcripts in and close to various domains of Fgf8 action, including the prospective midbrain-hindbrain region, the somites, the neural crest, the forebrain, and developing eyes. Morpholino-oligomer-assisted gene knock-down experiments targeted against fgf8 and fgf3 suggest that Fgf3 and Fgf8 are co-regulators of these genes in the early forebrain anlage. Furthermore, inhibition of Fgf signaling by overexpression of sprouty4 or application of the Fgf inhibitor SU5402 leads to a loss of all erm and pea3 expression domains. Conversely, ectopically provided fgf3 mRNA or implanted beads coated with Fgf8 elicit ectopic transcription of erm and pea3. Both activation and loss of transcripts can be observed within short time frames. We conclude that both the transcriptional onset and maintenance of these factors are tightly coupled to Fgf signaling and propose that erm and pea3 transcription is a direct readout of cells to Fgf levels. Given the knowledge that has accumulated on the posttranslational control of ETS domain factors and their combinatorial interactions with other transcription factors, we suggest that the close coupling of erm and pea3 transcription to Fgf signaling might serve to integrate Fgf signaling with other signals to establish refined patterns in embryonic development.

The PEA3 group of ETS-related transcription factors. Role in breast cancer metastasis

The ets genes encode eukaryotic transcription factors that are involved in tumorigenesis and developmental processes. The signature of the Ets family is the ETS-domain, which binds to sites containing a central 5'-GGAA/T-3' motif. They can be sub-classified primarily because of the high amino acid conservation in their ETS-domains and, in addition, in the conservation of other domains generally characterized as transactivating. This is the case for the PEA3 group, which is currently made up of three members, PEA3/E1AF, ER81/ETV1 and ERM, which are more than 95% identical in the ETS-domain and more than 85% in the transactivation acidic domain. The members of the PEA3 group are activated through both the Ras-dependent and other kinase pathways, a function which emphasizes their involvement in several oncogenic mechanisms. The expression pattern of the three PEA3 group genes during mouse embryogenesis suggests that they are differentially regulated, probably to serve important functions such as tissue interaction. Although the target genes of these transcription factors are multiple, their most frequently studied role concerns their involvement in the metastatic process. In fact, PEA3 group members are over-expressed in metastatic human breast cancer cells and mouse mammary tumors, a feature which suggests a function of these transcription factors in mammary oncogenesis. Moreover, when they are ectopically over-expressed in non-metastatic breast cancer cells, these latter become metastatic with the activation of transcription of matrix metalloproteinases or adhesion molecules, such as ICAM-1.

The PEA3 Ets transcription factor comprises multiple domains that regulate transactivation and DNA binding

PEA3, a member of the Ets family of transcription factors, is a nuclear phosphoprotein capable of activating transcription. Mouse PEA3 comprises 480 amino acids and bears an approximately 85-amino acid ETS domain near its carboxyl terminus. Whereas analyses of bacterially expressed PEA3 revealed that the ETS domain is required for sequence-specific DNA binding, little is known of the functional domains in the protein required for its activity in mammalian cells. To this end, we defined the location of the PEA3 functional domains in COS cells. PEA3 bears a strong activation domain near its amino terminus, which is flanked by two regions that independently negatively regulate its activity. PEA3 expressed in COS cells was incapable of binding to DNA in vitro. However, DNA binding activity could be unmasked by incubation with a PEA3-specific antibody. Analyses of the DNA binding activity of PEA3 deletion mutants revealed that two regions flanking the ETS domain independently inhibited DNA binding; deletion of both regions was required to detect DNA binding in the absence of a PEA3-specific antibody. Under these conditions, the ETS domain was sufficient for sequence-specific DNA binding. These findings suggest that the activity of PEA3 is exquisitely controlled at multiple functional levels.

Role of Ets transcription factors in mammary gland development and oncogenesis

PEA3 is the founding member of a subfamily of closely related ets genes that includes ER81 and ERM. PEA3 is expressed in the epithelial cells of mammary buds at the time that these first appear during mouse embryogenesis, and it is differentially expressed during postnatal mammary gland development. PEA3 expression is highest at the onset of puberty and during early pregnancy, times of extensive epithelial outgrowth and branching. PEA3 is expressed in undifferentiated epithelial cap cells of terminal end buds, and in differentiated myoepithelial cells of ducts and alveoli. Loss-of-function mutations in the PEA3 gene compromise mammary ductal branching at the onset of puberty and early during pregnancy. PEA3 is overexpressed in the vast majority of human breast tumors and in nearly all of the HER2-positive subclass of such tumors. PEA3 is similarly overexpressed in transgenic mouse models of this malignancy. Expression of dominant-negative PEA3 in the mouse mammary gland of MMTV-HER2 transgenic mice dramatically delays the onset and reduces the incidence of mammary tumors. Hence PEA3 and/or its close relatives play key regulatory roles in both mammary gland development and oncogenesis.

Expression and function of Ets transcription factors in mammalian development: a regulatory network

The Ets transcription factor family is involved in a variety of mammalian developmental processes at the cellular, tissue and organ levels. They are implicated in cellular proliferation, differentiation, migration, apoptosis and cell - cell interactions. This article reviews recent studies that demonstrate the integral importance of Ets in the dosage dependent regulation of development. The expression of many Ets genes is associated with mesenchymal - epithelial interactions and changes in extracellular matrix proteins. These inductive processes contribute to tissue remodeling and integrity, particularly during embryonic development. Overlapping as well as unique patterns of Ets expression are evident in developing tissues, including development of the lymphoid and myeloid lineages, brain and central nervous system, bone and mammary gland. Integration of these data will allow the development of predictive models for the regulation of complex developmental processes.

Phosphorylation of ETS transcription factor ER81 in a complex with its coactivators CREB-binding protein and p300

The ETS protein ER81 is a DNA-binding factor capable of enhancing gene transcription and is implicated in cellular transformation, but presently the mechanisms of its actions are unclear. In this report, ER81 is shown to coimmunoprecipitate with the transcriptional coactivator CREB-binding protein (CBP) and the related p300 protein (together referred to as CBP/p300). Moreover, confocal laser microscopic studies demonstrated that ER81 and p300 colocalized to nuclear speckles. In vitro and in vivo interaction studies revealed that ER81 amino acids 249 to 429, which encompass the ETS DNA-binding domain, are responsible for binding to CBP/p300. However, mutation of a putative protein-protein interaction motif, LXXLL, in the ETS domain of ER81 did not affect interaction with CBP/p300, whereas DNA binding of ER81 was abolished. Furthermore, two regions within CBP, amino acids 451 to 721 and 1891 to 2175, are capable of binding to ER81. Consistent with the physical interaction between ER81 and the coactivators CBP and p300, ER81 transcriptional activity was potentiated by CBP/p300 overexpression. Moreover, an ER81-associated protein kinase activity was enhanced upon p300 overexpression. This protein kinase phosphorylates ER81 on serines 191 and 216, and mutation of these phosphorylation sites increased ER81 transcriptional activity in Mv1Lu cells but not in HeLa cells. Altogether, our data elucidate the mechanism of how ER81 regulates gene transcription, through interaction with the coactivators CBP and p300 and an associated kinase that may cell type specifically modulate the ability of ER81 to activate gene transcription.

The human NAD+-dependent 15-hydroxyprostaglandin dehydrogenase gene promoter is controlled by Ets and activating protein-1 transcription factors and progesterone

NAD+-dependent 15-hydroxyprostaglandin dehydrogenase (PGDH) is a key catabolic enzyme in the inactivation of PGF2alpha and PGE2 and therefore serves as an important determinant in regulating their local concentrations. To gain insights into the transcriptional regulation of this enzyme, we have isolated 3.5 kb of the 5'-flanking sequence of the human PGDH promoter and characterized its control in hemopoietic cells and cells of myometrial and placental origin. Several potential binding sites for cAMP-responsive element-binding protein (CREB), Ets, and activating protein-1 (AP-1) transcription factors are present within 2368 bp of the 5'-flanking region. This region and deletions thereof were fused to the luciferase reporter gene and used for transient transfection experiments. In Jurkat leukemic T cells, which express PGDH endogenously, the transfected PGDH promoter was strongly induced by phorbol ester. Induction was reversed by coexpression of A-Fos, a dominant negative to AP-1. In primary cultures of myometrial smooth muscle cells (SMC), the Ets family members Ets-1, Ets-2, and PEA3 potently stimulated transcriptional activity of the PGDH promoter. PEA3-mediated activation was partially repressed by A-Fos, suggesting an involvement of AP-1 proteins, which might be conferred by a distal and a proximal Ets/ AP-1 composite element. The distal Ets/AP-1 element is flanked by two CRE-like sequences. Cotransfection of A-CREB, a dominant negative to CREB, inhibited stimulation of PGDH-2368/luc3 by PEA3 in myometrial SMC, whereas treatment with 8-bromo-cAMP moderately enhanced promoter activity. Progesterone is believed to be an important stimulus for PGDH expression in the utero-placental unit, thus contributing to the maintenance of a quiescent uterus during pregnancy. In myometrial SMC, both isoforms of the progesterone receptor, PR-B and PR-A, caused a ligand-dependent activation of PGDH-2368/luc3. Transcriptional activity of PR-B, but not PR-A, was further enhanced by the addition of 8-bromo-cAMP. We could not confirm a recently proposed transcriptional control of PGDH by mineralocorticoid receptor. No effect of mineralocorticoid receptor, in the absence or presence of aldosterone, with or without 8-bromo-cAMP, was observed on PGDH-2368/luc3. Taken together, these findings demonstrate control of the PGDH promoter by multiple pathways and provide evidence for cross-talk among Ets, AP-1, cAMP, and PR-mediated signaling, suggesting complex regulatory mechanisms for the expression of PGDH.

Genomic organization of the human e1af gene,a member of Ets transcription factors

The E1AF protein belongs to the family of Ets transcription factors and is involved in the regulation of metastasis gene expression. It has recently been reported in an undifferentiated child sarcoma that part of this gene could be fused by translocation to the ews gene. We show here that the human e1af gene, which is located in the q21 region of chromosome 17, is organized in 13 exons distributed along 19kb of genomic DNA. Its two main functional domains, the acidic domain and the DNA-binding ETS domain, are each encoded by three different exons. The 3'-untranslated region of e1af is 0.7kb. The 5'-untranslated region is about 0.3kb and is composed of a first exon upstream from the exon containing the first methionine. These data could possibly accelerate an understanding of the molecular basis of putative inherited diseases linked to E1AF.

Molecular genetics of chromosome translocations involving EWS and related family members

Many types of sarcomas are characterized by specific chromosomal translocations that appear to result in the production of novel, tumor-specific chimeric transcription factors. Many of these show striking similarities: the emerging picture is that the amino-terminal domain of the fusion product is donated by the Ewing's sarcoma gene (EWS) or a related member from the same gene family, whereas the carboxy-terminal domain often consists of a DNA-binding domain derived from one of a number of transcription factors. Given the observation that the different translocation partners of the EWS protooncogene are associated with distinct types of sarcomas, the functional consequence of fusing EWS (or a related family member) to a different DNA-binding domain can only be understood in the context of functional studies that define the specificity of action of the different fusion products. An understanding of the molecular structure and function of these translocations provides new methods for diagnosis and novel targets for therapeutics.

Characterization of the human and mouse ETV1/ER81 transcription factor genes: role of the two alternatively spliced isoforms in the human

The Ets transcription factors of the PEA3 group--E1AF/PEA3, ETV1/ER81 and ERM--are almost identical in the ETS DNA-binding and the transcriptional acidic domains. To accelerate our understanding of the molecular basis of putative diseases linked to ETV1 such as Ewing's sarcoma we characterized the human ETV1 and the mouse ER81 genes. We showed that these genes are both encoded by 13 exons in more than 90 kbp genomic DNA, and that the classical acceptor and donor splicing sites are present in each junction except for the 5' donor site of intron 9 where GT is replaced by TT. The genomic organization of the ETS and acidic domains in the human ETV1 and mouse ER81 (localized to chromosome 12) genes is similar to that observed in human ERM and human E1AF/PEA3 genes. Moreover, as in human ERM and human E1AF/PEA3 genes, a first untranslated exon is upstream from the first methionine, and the mouse ER81 gene transcription is regulated by a 1.8 kbp of genomic DNA upstream from this exon. In human, the alternative splicing of the ETV1 gene leads to the presence (ETV1 alpha) or the absence (ETV1 beta) of exon 5 encoding the C-terminal part of the transcriptional acidic domain, but without affecting the alpha helix previously described as crucial for transactivation. We demonstrated here that the truncated isoform (human ETV1 beta) and the full-length isoform (human ETV1 alpha) bind similarly specific DNA Ets binding sites. Moreover, they both activate transcription similarly through the PKA-transduction pathway, so suggesting that this alternative splicing is not crucial for the function of this protein as a transcription factor. The comparison of human ETV1 alpha and human ETV1 beta expression in the same tissues, such as the adrenal gland or the bladder, showed no clear-cut differences. Altogether, these data open a new avenue of investigation leading to a better understanding of the functional role of this transcription factor.

The Xenopus Ets transcription factor XER81 is a target of the FGF signaling pathway

We report the cloning of a cDNA encoding a Xenopus laevis Ets-type transcription factor. This new Xenopus gene belongs to the PEA3 subfamily of Ets proteins and shows the highest degree of sequence similarity to the mouse and human ER81 genes. The Xenopus ER81 gene (XER81) is transcribed in the embryo after mid blastula transition (MBT) and three transcripts of 3, 4 and 6 kb are detected throughout embryogenesis. XER81 mRNA is localized in the animal pole of the late blastula stage and higher levels of XER81 transcripts are detected in the marginal zone at the onset of gastrulation. In later embryogenesis XER81 transcripts are found in neural crest cells, eyes, otic vesicles and pronephros. The transcription of XER81 can be stimulated by bFGF and eFGF in animal and vegetal cap explants. Expression of the dominant negative FGF receptor mutant in animal caps and embryos blocks XER81 transcription, arguing that the expression of this Ets gene requires active FGF signaling. The spatial overlap of eFGF and XER81 expression domains supports the idea that XER81 transcription could be a marker for regions with active FGF signaling in the embryo.

Cell-type specific factors bind to regulatory elements located downstream of the TATA-box element in the mouse myelin basic protein (MBP) gene promoter

Cell-type specific transcription of the myelin basic protein (MBP) gene in primary oligodendrocytes (OL) is regulated by cis-acting regulatory elements located at both upstream and downstream of the TATA-box region of the MBP promoter. To identify cell-type specific factors that bind to the downstream regulatory elements, we utilised DNase I footprinting analysis and gel retardation assays with nuclear extracts from myelin-forming OL as well as a non-myelin forming cell line, C6 glioma (C6) cells. Several regions of DNA were protected from DNAse I digestion by nuclear extracts of both cell types. However, two regions, from -17 to +17 and from +47 to +58 were protected specifically in OL, while three regions, from + 17 to + 22, from +43 to +49 and from +58 to +64 were protected only with C6 nuclear extracts. Inspection of the protected regions for homology with known transcription factor binding sites revealed that sequences at from +47 to +58 and from +56 to +68 showed extensive homology to the negative regulatory element (NRE1), of the mouse renin gene and to the interferon (IFN) consensus sequence of major histocompatibility complex class I genes (MHC I-ICS), respectively. Gel retardation assays using a MHC I-ICS oligonucleotide and transient transfection assays using MBP-CAT constructs were used to study the effect of IFNs on MBP promoter activity in OL and C6 cells. In OL, IFN-alpha/beta caused little induction of CAT activity, but IFN-gamma resulted in a 2-3.5-fold decrease in CAT activity. In contrast, in C6 cells both IFN-alpha/beta and IFN-gamma induced a 1.5-2.5-fold increase in CAT activity. The cooperative effects of factors binding to NREs and ICS may be responsible for the cell-type specific regulation of MBP gene transcription.

A novel ets-related transcription factor, ERT/ESX/ESE-1, regulates expression of the transforming growth factor-beta type II receptor

A 2.5-kilobase cDNA clone that encodes a 371-amino acid novel transcription factor was isolated from a human placenta cDNA library using a yeast one-hybrid system. The novel ets-related transcription factor (ERT) showed a homology with the ETS DNA-binding domain. Using constructs of the transforming growth factor-beta (TGF-beta) type II receptor (RII) promoter linked to the luciferase gene, we have demonstrated that ERT activates transcription of the TGF-beta RII gene through the 5'-TTTCCTGTTTCC-3' response element spanning nucleotides +13 to +24 and multiple additional ETS binding sites between -1816 and -82 of the TGF-beta RII promoter. A specific interaction between ERT and the ETS binding sites was also demonstrated using an electrophoretic mobility shift assay. Deletion mapping of ERT protein suggests that the transactivation domain resides in the amino terminus while the DNA-binding domain is localized to the carboxyl-terminal region. Our results suggest that ERT might be a major transcription factor involved in the transcriptional regulation of the TGF-beta RII gene.

Expression of E1AF, an ets-family transcription factor, is correlated with the invasive phenotype of oral squamous cell carcinoma

E1AF is a newly identified ets-oncogene family transcription factor. Previous reports have noted that E1AF can upregulate promoter activities of several matrix metalloproteinase (MMP) genes and showed that invasive potentials of oral squamous cell carcinoma-derived cell lines are correlated with expression of E1AF and MMPs. The invasive phenotype is restrained by transfection with an antisense E1AF expression vector. Thus, E1AF is thought to be highly correlated with malignant potentials of cancer cells. However, little is known about E1AF expression and cancer cell malignancies in in vivo tumours. In the present study, 27 oral squamous cell carcinoma (SCC) specimens were examined using RT-PCR, Southern blot hybridisation and in situ hybridisation (ISH) and compared to the clinicopathological parameters. Among the 27 patients, E1AF was detected in 15 cases. E1AF mRNA was detected in 13 of 17 invasive SCCs, whereas the majority of SCCs not expressing E1AF showed an expansive growth pattern. Increased prevalence of E1AF-positive oral SCC was observed in cases with nodal metastasis. These results indicate that E1AF may be involved in cancer cell malignancies through its ability to promote invasive potential.

Structure-function relationships of the PEA3 group of Ets-related transcription factors

The PEA3 group of transcription factors belongs to the Ets family and is composed of PEA3, ERM, and ER81, which are more than 95% identical within the DNA-binding domain--the ETS domain--and which demonstrate 50% aa identity overall. We present here a review of the current knowledge of these transcription factors, which possess functional domains responsible for DNA-binding, DNA-binding inhibition, and transactivation. Recent data suggest that these factors are targets for signaling cascades, such as the Ras-dependent ones, and thus may contribute first to the nuclear response to cell stimulation and second to Ras-induced cell transformation. The expression of the PEA3 group members in numerous developing murine organs, and, especially, in epithelial-mesenchymal interaction events, suggests a key role in murine organogenesis. Moreover, their expression in certain breast cancer cells suggests a possible involvement of these genes in the appearance, progression, and invasion of malignant cells.

Activation of the p21(Waf1/Cip1) promoter by the ets oncogene family transcription factor E1AF

p21(Waf1/Cip1) is one of the key regulatory proteins in cell cycle, terminal differentiation, and apoptosis. Its promoter was shown to be transactivated by the wild-type p53 protein as well as in a p53-independent manner. In this report, we demonstrate that E1AF, an ets-related transcription factor, activates the human p21(Waf1/Cip1) promoter by interacting with the ets-binding sites located close to the two previously identified p53-responsive elements. Northern blot analysis revealed that p21(Waf1/Cip1) and E1AF were correlatively upregulated in response to cisplatin treatment in SiHa cells. Transient expression assays demonstrated that E1AF can activate the p21(Waf1/Cip1) promoter-driven luciferase reporter gene in SiHa cells. The p21(Waf1/Cip1) promoter activity was also increased in p53-null Saos2 osteosarcoma cells, but was markedly reduced when the ets-binding sites were deleted. These results indicate that E1AF positively regulates transcription from the p21(Waf1/Cip1) promoter in response to genotoxic stresses.

Antisense E1AF transfection restrains oral cancer invasion by reducing matrix metalloproteinase activities

E1AF is a newly identified human ets-family transcription factor. We have reported that E1AF can up-regulate transcription of matrix metalloproteinase (MMP) genes and confers invasive phenotype on human cancer cells. HSC3 is an oral squamous-cell-carcinoma-derived cell line, and it manifests high levels of E1AF and MMP-1 and -9 gene expression that are associated with invasive potential. We reconstructed an E1AF antisense expression vector, transfected HSC3 cells with the vector, and obtained HSC3AS cells that express E1AF antisense RNA. HSC3AS showed decreasing mRNA and protein levels of MMP-1, -3, and -9. Moreover, HSC3AS showed lower invasive potential in vitro three-dimensional raft culture and in vivo implantation into nude mice. These results imply that transfection of antisense E1AF inhibits tumor invasion by down-regulating MMP genes.

Two transcription factors, E1AF and N-myc, correlate with the invasiveness of neuroblastoma cell lines

The ets transcription factor E1AF can activate several matrix-degrading metalloproteinase (MMP) genes and is implicated in enhancement of tumor cell invasion. Here we compared the invasive activity of five human neuroblastoma cell lines (TGW, GOTO, SK-N-BE, SK-N-SH and SK-N-AS), which exhibit distinct levels of N-myc amplification, together with the expression of E1AF. Extracellular matrix-degrading proteases and their inhibitor proteins, which play an important role in local invasion, were also analyzed. The activity to invade through reconstituted basement membrane was high in cells (TGW, GOTO, and SK-N-BE) with N-myc amplification, and these cells produced relatively large amounts of E1AF mRNA, correlating with the invasive activities. Of several matrix metalloproteinases (MMPs) and a tissue inhibitor of MMPs (TIMP), only membrane-bound type 1 MMP (MT1-MMP) was specifically detected in N-myc-amplified cells, suggesting a role of MT1-MMP in neuroblastoma cell invasion. MMP-2 (72 kD type IV collagenase), TIMP-1 and TIMP-2 were expressed in all five cell lines. Urokinase-type plasminogen activator was undetectable. These findings indicate that the transcription factors E1AF and N-myc are related to malignant phenotypes of neuroblastoma.