The Ets-1 and Ets-2 transcription factors activate the promoters for invasion-associated urokinase and collagenase genes in response to epidermal growth factor

ERK/MAPK Signalling Pathway Regulates MMP2 through ETS1 in Renal Clear Cell Carcinoma

BACKGROUND

The c-ETS-1 (ETS1) expression is high in clear cell renal cell carcinoma (ccRCC) tissues; however, how it impacts ccRCC is currently unknown.

METHODS

The online STRING web source was used to construct a protein network interacting with ETS1. The Cell Counting Kit-8 was used to detect the cell viability. A clonogenic assay, a wound-healing assay, and a Transwell assay were used to detect cell proliferation, invasion and migration abilities. Western blot was used to detect the expression of proteins.

RESULTS

The data showed the expression of ETS1 in ccRCC tissues to be significantly increased compared to adjacent tissues (p<0.05). The positive expression of ETS1 in ccRCC patients aged 20-100 was statistically significant compared to adjacent normal tissues (p<0.05). The grade of ETS1 positive expression (1-4) and lymph node metastasis (N1) in ccRCC were significantly higher than those in adjacent normal tissues (p<0.05). The tumour stage (stages 1-4) in ccRCC patients with positive ETS1 expression was significantly higher than that in adjacent normal tissues (p<0.05). Knockdown of ETS1 and PERK inhibitors significantly inhibited the proliferation, migration and invasion of ccRCC cells. Knockdown of ETS1 inhibited MMP-2 expression, and an extracellular signal-related kinase (ERK) inhibitor inhibited both ETS1 and MMP-2 expression.

CONCLUSION

A high expression of ETS1 is associated with the progression of ccRCC. This study suggests that ETS1 promotes proliferation by increasing MMP2 expression in ccRCC, and combined knockdown of ETS1 and inhibition of ERK can significantly inhibit the proliferation, migration and invasion of ccRCC. ETS1 may be a therapeutic and prognostic target for renal cell carcinoma.

The urothelial gene regulatory network: understanding biology to improve bladder cancer management

The urothelium is a stratified epithelium composed of basal cells, one or more layers of intermediate cells, and an upper layer of differentiated umbrella cells. Most bladder cancers (BLCA) are urothelial carcinomas. Loss of urothelial lineage fidelity results in altered differentiation, highlighted by the taxonomic classification into basal and luminal tumors. There is a need to better understand the urothelial transcriptional networks. To systematically identify transcription factors (TFs) relevant for urothelial identity, we defined highly expressed TFs in normal human bladder using RNA-Seq data and inferred their genomic binding using ATAC-Seq data. To focus on epithelial TFs, we analyzed RNA-Seq data from patient-derived organoids recapitulating features of basal/luminal tumors. We classified TFs as "luminal-enriched", "basal-enriched" or "common" according to expression in organoids. We validated our classification by differential gene expression analysis in Luminal Papillary vs. Basal/Squamous tumors. Genomic analyses revealed well-known TFs associated with luminal (e.g., PPARG, GATA3, FOXA1) and basal (e.g., TP63, TFAP2) phenotypes and novel candidates to play a role in urothelial differentiation or BLCA (e.g., MECOM, TBX3). We also identified TF families (e.g., KLFs, AP1, circadian clock, sex hormone receptors) for which there is suggestive evidence of their involvement in urothelial differentiation and/or BLCA. Genomic alterations in these TFs are associated with BLCA. We uncover a TF network involved in urothelial cell identity and BLCA. We identify novel candidate TFs involved in differentiation and cancer that provide opportunities for a better understanding of the underlying biology and therapeutic intervention.

CDK10 suppresses metastasis of lung adenocarcinoma through inhibition of the ETS2/c-Raf/p-MEK/p-ERK signaling loop

The repertoire of aberrant signaling underlying the pathogenesis of lung adenocarcinoma remains largely uncharacterized, which precludes an efficient therapy for these patients, especially when distant metastasis occurs. Cyclin-dependent kinase 10 (CDK10) has been reported to modulate the progression of malignant tumors; however, contradictory effects have been found among different types of malignant tumors. In the present study, we found that CDK10 was downregulated in lung adenocarcinoma compared with the paired adjacent normal lung tissue, and lower expression level of CDK10 was associated with more frequent N2 staged lymph node and distant metastasis, higher TNM stage, and shorter overall survival. Further study indicated that CDK10 inhibited the migration and invasion abilities with no impact on the proliferation of lung adenocarcinoma cells. Mechanistically, CDK10 could bind to and promote the degradation of ETS2, a transcription factor for C-RAF and MMP2/9, thereby inactivating the downstream c-Raf/p-MEK/p-ERK pathway that drives epithelial-mesenchymal transition and impairing the expression of matrix metalloproteinases involved in cell invasion. In addition, the p-MEK/p-ERK pathway conducts a positive feedback regulation on the expression of ETS2. Knockdown of CDK10 in human lung adenocarcinoma cells significantly promoted the formation of metastatic foci in lungs in a xenograft mouse model. In conclusion, CDK10 suppresses metastasis of lung adenocarcinoma by disrupting the ETS2/c-Raf/p-MEK/p-ERK/ETS2 signaling and MMP2/9, providing a new therapeutic target for the treatment of lung adenocarcinoma with metastasis.

Microfat exerts an anti-fibrotic effect on human hypertrophic scar via fetuin-A/ETV4 axis

BACKGROUND

Hypertrophic scar is a fibrotic disease following wound healing and is characterized by excessive extracellular matrix deposition. Autologous microfat grafting proves an effective strategy for the treatment thereof as it could improve the texture of scars and relieve relevant symptoms. This study aims to explore the potential mechanisms underlying the anti-fibrotic effect of microfat on hypertrophic scars.

METHODS

In this study, we injected microfat into transplanted hypertrophic scars in mouse models and investigated the subsequent histological changes and differential expression of mRNAs therein. As for in vitro studies, we co-cultured microfat and hypertrophic scar fibroblasts (HSFs) and analyzed molecular profile changes in HSFs co-cultured with microfat by RNA sequencing. Moreover, to identify the key transcription factors (TFs) which might be responsible for the anti-fibrotic function of microfat, we screened the differentially expressed TFs and transfected HSFs with lentivirus to overexpress or knockdown certain differentially expressed TFs. Furthermore, comparative secretome analyses were conducted to investigate the proteins secreted by co-cultured microfat; changes in gene expression of HSFs were examined after the administration of the potential anti-fibrotic protein. Finally, the relationship between the key TF in HSFs and the microfat-secreted anti-fibrotic adipokine was analyzed.

RESULTS

The anti-fibrotic effect of microfat was confirmed by in vivo transplanted hypertrophic scar models, as the number of α-SMA-positive myofibroblasts was decreased and the expression of fibrosis-related genes downregulated. Co-cultured microfat suppressed the extracellular matrix production of HSFs in in vitro experiment, and the transcription factor ETV4 was primarily differentially expressed in HSFs when compared with normal skin fibroblasts. Overexpression of ETV4 significantly decreased the expression of fibrosis-related genes in HSFs at both mRNA and protein levels. Fetuin-A secreted by microfat could also downregulate the expression of fibrosis-related genes in HSFs, partially through upregulating ETV4 expression.

CONCLUSIONS

Our results demonstrated that transcription factor ETV4 is essential for the anti-fibrotic effect of microfat on hypertrophic scars, and that fetuin-A secreted by microfat could suppress the fibrotic characteristic of HSFs through upregulating ETV4 expression. Microfat wields an alleviative influence over hypertrophic scars via fetuin-A/ETV4 axis.

The Multiple Roles of CD147 in the Development and Progression of Oral Squamous Cell Carcinoma: An Overview

Cluster of differentiation (CD)147, also termed extracellular matrix metalloprotease inducer or basigin, is a glycoprotein ubiquitously expressed throughout the human body, the oral cavity included. CD147 actively participates in physiological tissue development or growth and has important roles in reactive processes such as inflammation, immunity, and tissue repair. It is worth noting that deregulated expression and/or activity of CD147 is observed in chronic inflammatory or degenerative diseases, as well as in neoplasms. Among the latter, oral squamous cell carcinoma (OSCC) is characterized by an upregulation of CD147 in both the neoplastic and normal cells constituting the tumor mass. Most interestingly, the expression and/or activity of CD147 gradually increase as healthy oral mucosa becomes inflamed; hyperplastic/dysplastic lesions are then set on, and, eventually, OSCC develops. Based on these findings, here we summarize published studies which evaluate whether CD147 could be employed as a marker to monitor OSCC development and progression. Moreover, we describe CD147-promoted cellular and molecular events which are relevant to oral carcinogenesis, with the aim to provide useful information for assessing whether CD147 may be the target of novel therapeutic approaches directed against OSCC.

Glycogen synthase kinase-3 beta (GSK3β)-mediated phosphorylation of ETS1 promotes progression of ovarian carcinoma

ETS1 - an evolutionarily conserved transcription factor involved in the regulation of a number of cellular processes - is overexpressed in several malignancies, including ovarian cancer. Most studies on ETS1 expression have been focused on the transcriptional and RNA levels, with post-translational control mechanisms remaining relatively unexplored in the pathogenesis of malignancies. Here, we show that ETS1 forms a complex with glycogen synthase kinase-3β (GSK3β). Specifically, GSK3β-mediated phosphorylation of ETS1 at threonine 265 and serine 269 promoted protein stability, induced the transcriptional activation of matrix metalloproteinase (MMP)-9, and increased cell migration. In vivo experiments revealed that a GSK3β inhibitor was able to suppress both endogenous ETS1 expression and induction of MMP-9 expression. Upon generation of a specific antibody against phosphorylated ETS1, we demonstrated that phospho-ETS1 immunohistochemical expression in ovarian cancer specimens was correlated with that of MMP-9. Notably, the cumulative overall survival of patients with low phospho-ETS1 histoscores was significantly longer than that of those showing higher scores. We conclude that the GSK3β/ETS1/MMP-9 axis may regulate the biological aggressiveness of ovarian cancer and can serve as a prognostic factor in patients with this malignancy.

Prognostic significance of uPA and uPAR expression in patients with cervical cancer undergoing radiotherapy

Cervical cancer remains a major health threat. Urokinase serves as a marker of metastatic tumors. The present study aimed to determine whether the expression levels of urokinase plasminogen activator (uPA) and urokinase plasminogen activator receptor (uPAR), before and during the course of radiotherapy, serve as prognostic markers for patients with cervical cancer. Cervical tumor tissue biopsies were collected from 72 patients before radiotherapy and after the completion of external beam radiotherapy (EBRT) before intracavitary brachytherapy. The levels of uPA and uPAR were determined using ELISA assays. The significance of the associations between the protein expression levels and the clinical outcomes of patients was determined. Although irradiation enhanced uPA and uPAR expression in cervical cancer cell lines, average uPA levels significantly decreased in tumors, and uPAR levels significantly increased after EBRT. The levels of uPA increased in 12 patients and decreased in 26 patients; and those of uPAR increased in 13 patients and decreased in two patients. Cox regression analysis revealed that increased expression of uPAR was significantly associated with 5-year overall survival rate [hazard ratio (HR), 3.65; 95% confidence interval (CI), 1.18-11.30]. However, the levels of both proteins before radiotherapy failed to predict clinical outcomes. Other significant predictive factors were partial response (HR 7.22; 95% CI 1.17-44.73) and disease progression (HR, 13.41; 95% CI, 1.17-153.07). These findings indicated that increased expression of uPAR in cervical tumor tissue during radiotherapy may serve as a prognostic marker for patients with cervical cancer.

Transcription Factors in Cancer Development and Therapy

Cancer is a multi-step process and requires constitutive expression/activation of transcription factors (TFs) for growth and survival. Many of the TFs reported so far are critical for carcinogenesis. These include pro-inflammatory TFs, hypoxia-inducible factors (HIFs), cell proliferation and epithelial-mesenchymal transition (EMT)-controlling TFs, pluripotency TFs upregulated in cancer stem-like cells, and the nuclear receptors (NRs). Some of those, including HIFs, Myc, ETS-1, and β-catenin, are multifunctional and may regulate multiple other TFs involved in various pro-oncogenic events, including proliferation, survival, metabolism, invasion, and metastasis. High expression of some TFs is also correlated with poor prognosis and chemoresistance, constituting a significant challenge in cancer treatment. Considering the pivotal role of TFs in cancer, there is an urgent need to develop strategies targeting them. Targeting TFs, in combination with other chemotherapeutics, could emerge as a better strategy to target cancer. So far, targeting NRs have shown promising results in improving survival. In this review, we provide a comprehensive overview of the TFs that play a central role in cancer progression, which could be potential therapeutic candidates for developing specific inhibitors. Here, we also discuss the efforts made to target some of those TFs, including NRs.

Transcription Factors in Cancer Development and Therapy

Cancer is a multi-step process and requires constitutive expression/activation of transcription factors (TFs) for growth and survival. Many of the TFs reported so far are critical for carcinogenesis. These include pro-inflammatory TFs, hypoxia-inducible factors (HIFs), cell proliferation and epithelial-mesenchymal transition (EMT)-controlling TFs, pluripotency TFs upregulated in cancer stem-like cells, and the nuclear receptors (NRs). Some of those, including HIFs, Myc, ETS-1, and β-catenin, are multifunctional and may regulate multiple other TFs involved in various pro-oncogenic events, including proliferation, survival, metabolism, invasion, and metastasis. High expression of some TFs is also correlated with poor prognosis and chemoresistance, constituting a significant challenge in cancer treatment. Considering the pivotal role of TFs in cancer, there is an urgent need to develop strategies targeting them. Targeting TFs, in combination with other chemotherapeutics, could emerge as a better strategy to target cancer. So far, targeting NRs have shown promising results in improving survival. In this review, we provide a comprehensive overview of the TFs that play a central role in cancer progression, which could be potential therapeutic candidates for developing specific inhibitors. Here, we also discuss the efforts made to target some of those TFs, including NRs.

ADAM9 Mediates Triple-Negative Breast Cancer Progression via AKT/NF-κB Pathway

Upregulation of a disintegrin and metalloprotease 9 (ADAM9) is correlated with progression of cancers, such as prostate, bladder, and pancreatic cancers. However, its role in triple-negative breast cancer (TNBC) is still unclear. Our study aimed to investigate whether ADAM9 is upregulated and promoted the aggressiveness in TNBC. Breast cancer cell lines and patient specimens were used to evaluate the ADAM9 expression by western blotting and immunohistochemistry staining, respectively. Compared with the non-TNBC, ADAM9 expression was significantly increased in TNBC cells and TNBC patient specimens. Based on the data acquired from public databases, the correlation between ADAM9 expression and breast cancer patient survival was analyzed by Kaplan-Meier method. It was shown that ADAM9 overexpression was significantly correlated with poorer survival in patients with TNBC. Furthermore, ADAM9 in TNBC cells was knocked down by small interference RNA and then studied by the MTT/colony formation assay, wound healing assay and transwell invasion assay on the cell proliferation, migration, and invasion, respectively. We found that inhibiting ADAM9 expression suppressed TNBC cell proliferation, migration, and invasion by lowering the activation of AKT/NF-κB pathway. Our results demonstrated that ADAM9 is an important molecule in mediating TNBC aggressiveness and may be a potential useful therapeutic target in TNBC treatment.

ETS2 promotes epithelial-to-mesenchymal transition in renal fibrosis by targeting JUNB transcription

Epithelial-to-mesenchymal transition (EMT) plays an important role in the progression of renal tubulointerstitial fibrosis, a common mechanism leading to end-stage renal failure. V-ets erythroblastosis virus E26 oncogene homolog 2 (ETS2), a transcription factor, exhibits diverse roles in pathogenesis; however, its role in renal fibrosis is not yet fully understood. In this study, we detected the expression of ETS2 in an animal model of renal fibrosis and evaluated the potential role of ETS2 in tubular EMT induced by TGF-β1. We found that ETS2 and profibrogenic factors, alpha-smooth muscle actin (α-SMA) and fibronectin (FN), were significantly increased in the unilateral ureteral obstruction (UUO)-induced renal fibrosis model in mice. In vitro, TGF-β1 induced a high expression of ETS2 dependent on Smad3 and ERK signaling pathway in human proximal tubular epithelial cells (HK2). Knockdown of ETS2 abrogated TGF-β1-mediated expression of profibrogenic factors vimentin, α-SMA, collagen I, and FN in HK2 cells. Mechanistically, ETS2 promoted JUNB expression in HK2 cells after TGF-β1 stimulation. Furthermore, luciferase and Chromatin Immunoprecipitation (ChIP) assays revealed that the binding of ETS2 to three EBS motifs on the promoter of JUNB triggered its transcription. Notably, silencing JUNB reversed the ETS2-induced upregulation of the profibrogenic factors in HK2 cells after TGF-β1 stimulation. These findings suggest that ETS2 mediates TGF-β1-induced EMT in renal tubular cells through JUNB, a novel pathway for preventing renal fibrosis.

CHG: A Systematically Integrated Database of Cancer Hallmark Genes

Background

The analysis of cancer diversity based on a logical framework of hallmarks has greatly improved our understanding of the occurrence, development and metastasis of various cancers.

Methods

We designed Cancer Hallmark Genes (CHG) database which focuses on integrating hallmark genes in a systematic, standard way and annotates the potential roles of the hallmark genes in cancer processes. Following the conceptual criteria description of hallmark function the keywords for each hallmark were manually selected from the literature. Candidate hallmark genes collected were derived from 301 pathways of KEGG database by Lucene and manually corrected.

Results

Based on the variation data, we finally identified the hallmark genes of various types of cancer and constructed CHG. And we also analyzed the relationships among hallmarks and potential characteristics and relationships of hallmark genes based on the topological structures of their networks. We manually confirm the hallmark gene identified by CHG based on literature and database. We also predicted the prognosis of breast cancer, glioblastoma multiforme and kidney papillary cell carcinoma patients based on CHG data.

Conclusions

In summary, CHG, which was constructed based on a hallmark feature set, provides a new perspective for analyzing the diversity and development of cancers.

Transcriptional regulation of Hepatic Stellate Cell activation in NASH

Non-alcoholic steatohepatitis (NASH) signified by hepatic steatosis, inflammation, hepatocellular injury, and fibrosis is a growing cause of chronic liver disease, cirrhosis, and hepatocellular carcinoma. Hepatic fibrosis resulting from accumulation of extracellular matrix proteins secreted by hepatic myofibroblasts plays an important role in disease progression. Activated hepatic stellate cells (HSCs) have been identified as the primary source of myofibroblasts in animal models of hepatotoxic liver injury; however, so far HSC activation and plasticity have not been thoroughly investigated in the context of NASH-related fibrogenesis. Here we have determined the time-resolved changes in the HSC transcriptome during development of Western diet- and fructose-induced NASH in mice, a NASH model recapitulating human disease. Intriguingly, HSC transcriptional dynamics are highly similar across disease models pointing to HSC activation as a point of convergence in the development of fibrotic liver disease. Bioinformatic interrogation of the promoter sequences of activated genes combined with loss-of-function experiments indicates that the transcriptional regulators ETS1 and RUNX1 act as drivers of NASH-associated HSC plasticity. Taken together, our results implicate HSC activation and transcriptional plasticity as key aspects of NASH pathophysiology.

Increased expression of EHF via gene amplification contributes to the activation of HER family signaling and associates with poor survival in gastric cancer

The biological function of E26 transformation-specific (ETS) transcription factor EHF/ESE-3 in human cancers remains largely unknown, particularly gastric cancer. The aim of this study was to explore the role of EHF in tumorigenesis and its potential as a therapeutic target in gastric cancer. By using quantitative RT-PCR (qRT-PCR), immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) assays, we investigated the expression and copy number of EHF in a cohort of gastric cancers and control subjects. Specific EHF siRNAs was used to determine the biologic impacts and mechanisms of altered EHF expression in vitro and in vivo. Dual-luciferase reporter, chromatin immunoprecipitation (ChIP) and electrophoretic mobility shift assay (EMSA) assays were performed to identify its downstream targets. Our results demonstrated that EHF was significantly upregulated and frequently amplified in gastric cancer tissues as compared with control subjects. Moreover, EHF amplification was positively correlated with its overexpression and significantly associated with poor clinical outcomes of gastric cancer patients. We also found that EHF knockdown notably inhibited gastric cancer cell proliferation, colony formation, migration, invasion and tumorigenic potential in nude mice and induced cell cycle arrest and apoptosis. Importantly, we identified EHF as a new HER2 transcription factor and the modulator of HER3 and HER4 in gastric cancer. Collectively, our findings suggest that EHF is a novel functional oncogene in gastric cancer by regulating the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases and may represent a potential prognostic marker and therapeutic target for this cancer.

PYK2 integrates growth factor and cytokine receptors signaling and potentiates breast cancer invasion via a positive feedback loop

The involvement of ErbB family members in breast cancer progression and metastasis has been demonstrated by many studies. However, the downstream effectors that mediate their migratory and invasive responses have not been fully explored. In this study, we show that the non-receptor tyrosine kinase PYK2 is a key effector of EGFR and HER2 signaling in human breast carcinoma. We found that PYK2 is activated by both EGF and heregulin (HRG) in breast cancer cells, and positively regulates EGF/HRG-induced cell spreading, migration and invasion. PYK2 depletion markedly affects ERK1/2 and STAT3 phosphorylation in response to EGF/HRG as well as to IL8 treatment. Importantly, PYK2 depletion also reduced EGF/HRG-induced MMP9 and IL8 transcription, while IL8 inhibition abrogated EGF-induced MMP9 transcription and attenuated cell invasion. IL8, which is transcriptionally regulated by STAT3 and induces PYK2 activation, prolonged EGF-induced PYK2, STAT3 and ERK1/2 phosphorylation suggesting that IL8 acts through an autocrine loop to reinforce EGF-induced signals. Collectively our studies suggest that PYK2 is a common downstream effector of ErbB and IL8 receptors, and that PYK2 integrates their signaling pathways through a positive feedback loop to potentiate breast cancer invasion. Hence, PYK2 could be a potential therapeutic target for a subset of breast cancer patients.

High glucose and insulin enhance uPA expression, ROS formation and invasiveness in breast cancer-derived cells

BACKGROUND

Accumulating evidence indicates that type 2 diabetes is associated with an increased risk to develop breast cancer. This risk has been attributed to hyperglycemia, hyperinsulinemia and chronic inflammation. As yet, however, the mechanisms underlying this association are poorly understood. Here, we studied the effect of high glucose and insulin on breast cancer-derived cell proliferation, migration, epithelial-mesenchymal transition (EMT) and invasiveness, as well as its relationship to reactive oxygen species (ROS) production and the plasminogen activation system.

METHODS

MDA-MB-231 cell proliferation, migration and invasion were assessed using 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), scratch-wound and matrigel transwell assays, respectively. ROS production was determined using 2' 7'-dichlorodihydrofluorescein diacetate. The expression of E-cadherin, vimentin, fibronectin, urokinase plasminogen activator (uPA), its receptor (uPAR) and its inhibitor (PAI-1) were assessed using qRT-PCR and/or Western blotting assays, respectively. uPA activity was determined using gel zymography.

RESULTS

We found that high glucose stimulated MDA-MB-231 cell proliferation, migration and invasion, together with an increased expression of mesenchymal markers (i.e., vimentin and fibronectin). These effects were further enhanced by the simultaneous administration of insulin. In both cases, the invasion and growth responses were found to be associated with an increased expression of uPA, uPAR and PAI-1, as well as an increase in active uPA. An osmolality effect of high glucose was excluded by using mannitol at an equimolar concentration. We also found that all changes induced by high glucose and insulin were attenuated by the anti-oxidant N-acetylcysteine (NAC) and, thus, depended on ROS production.

CONCLUSIONS

From our data we conclude that hyperglycemia and hyperinsulinemia can promote breast cancer cell proliferation, migration and invasion. We found that these features were associated with increased expression of the mesenchymal markers vimentin and fibronectin, as well as increased uPA expression and activation through a mechanism mediated by ROS.

CDK7-dependent transcriptional addiction in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a highly aggressive form of breast cancer that exhibits extremely high levels of genetic complexity and yet a relatively uniform transcriptional program. We postulate that TNBC might be highly dependent on uninterrupted transcription of a key set of genes within this gene expression program and might therefore be exceptionally sensitive to inhibitors of transcription. Utilizing kinase inhibitors and CRISPR/Cas9-mediated gene editing, we show here that triple-negative but not hormone receptor-positive breast cancer cells are exceptionally dependent on CDK7, a transcriptional cyclin-dependent kinase. TNBC cells are unique in their dependence on this transcriptional CDK and suffer apoptotic cell death upon CDK7 inhibition. An "Achilles cluster" of TNBC-specific genes is especially sensitive to CDK7 inhibition and frequently associated with super-enhancers. We conclude that CDK7 mediates transcriptional addiction to a vital cluster of genes in TNBC and CDK7 inhibition may be a useful therapy for this challenging cancer.

Blockade of Ets-1 attenuates epidermal growth factor-dependent collagen loss in human carotid plaque smooth muscle cells

Although degradation of extracellular matrix by matrix metalloproteinases (MMPs) is thought to be involved in symptomatic (S) carotid plaques in atherosclerosis, the mechanisms of MMP expression are poorly understood. Here, we demonstrate that collagen loss in vascular smooth vessel cells (VSMCs) isolated from S plaques was induced by epidermal growth factor (EGF) through the activation of p38-MAPK and JNK-MAPK pathways. Inhibitors of p38-MAPK and JNK-MAPK signaling pathways downregulated the expression of MMP-1 and MMP-9. In addition, we examined whether v-ets erythroblastosis virus E26 oncogene homologue 1 (Ets-1), an important regulator of different genes, is involved in destabilizing S plaques in patients with carotid stenosis. We demonstrate that EGF induces Ets-1 expression and decreases interstitial and basement membrane collagen in vascular smooth muscle cells (VSMCs) from patients with carotid stenosis. Increased expression of MMP-1 and -9 and decreased collagen mRNA transcripts were also found in Ets-1-overexpressed VSMCs. Transfection with both dominant-negative form of Ets-1 and small interfering RNA blocked EGF-induced MMP-1 and -9 expressions and increased the mRNA transcripts for collagen I (α1) and collagen III (α1) in S compared with asymptomatic (AS) carotid plaques. Inhibitors of p38-MAPK (SB202190) and JNK-MAPK (SP600125) signaling pathways decreased the expression of Ets-1, MMP-1, and MMP-9 and increased collagen type I and III expression in EGF-treated VSMCs. This study provides a mechanistic insight into the role of Ets-1 in the plaque destabilization in patients with carotid stenosis involving p38-MAPK and JNK signaling pathways.

Docosahexaenoic Acid Downregulates EGF-Induced Urokinase Plasminogen Activator and Matrix Metalloproteinase 9 Expression by Inactivating EGFR/ErbB2 Signaling in SK-BR3 Breast Cancer Cells

Urokinase plasminogen activator (uPA) and matrix metalloproteinase 9 (MMP-9) play crucial roles in tumor metastasis. Despite the well-known anticancer role of docosa-hexaenoic acid (DHA), its specific effect on ErbB2-mediated breast cancer metastasis is not fully clarified. In this study, we investigated the effect of DHA on epidermal growth factor (EGF)-induced uPA and MMP-9 activity, expression and cell invasion in SK-BR3 breast cancer cells and the possible mechanisms involved. The results showed that EGF (40 ng/ml) induced uPA and MMP-9 mRNA and protein expression, enzyme activity, and 100 μM DHA significantly inhibited EGF-induced uPA and MMP-9 mRNA, protein expression, enzyme activity, cell migration, and cell invasion. EGF increased protein expression and phosphorylation of EGF receptor (EGFR) and ErbB2 as well as of JNK2, ERK1/2, and Akt, and these changes were attenuated by DHA pretreatment. AG1478, an inhibitor of EGFR, also attenuated EGF-induced activation of EGFR, JNK2, ERK1/2, and Akt. Knocked down ErbB2 expression resulted in a similar inhibition of uPA and MMP-9 expression as noted by DHA and AG1478. Taken together, these results suggest that suppression of EGF-induced metastasis by DHA is likely through an inhibition of EGFR and ErbB2 protein expression and the downstream target uPA and MMP-9 activation in SK-BR3 human breast cancer cells.

Urokinase is a negative modulator of Egf-dependent proliferation and motility in the two breast cancer cell lines MCF-7 and MDA-MB-231

The epidermal growth factor receptor (EGFR) is involved in the regulation of various cellular processes and dysregulation of its signalling plays a critical role in the etiology of a variety of malignancies like breast cancer. At the same time, elevated levels of urokinase (uPA), its receptor uPAR, and other components of the plasminogen activation system are found to be correlated with a poor prognosis in breast cancer. Interestingly, EGFR appears to participate in transducing the signal generated upon binding of uPA to uPAR. However, whether uPA signalling would thereby interfere with ligand-driven EGFR signalling was not described before. Therefore, it was the aim of the present study to investigate the combined effects of uPA and EGF in the low invasive and high invasive breast adenocarcinoma cell lines MCF-7 and MDA-MB-231, respectively. Simultaneous exposure of cells to both signals negatively affected ERK1/2 and AKT activation whereas positive effects on p38 and Src kinase phosphorylation were noted in both cell lines. Furthermore, uPA attenuated the mitogenic effect of EGF on cellular proliferation, invasion and motility in both MCF-7 and MDA-MB-231 cells. Experiments with the uPA amino terminal fragment (ATF) revealed that the negative effects of uPA were independent from its protease activity. Together, these data suggest that enhanced levels of uPA in breast cancer modulate the mitogenic effects of EGF and thus, this knowledge may help to better understand breast cancer pathogenesis as well as to develop new therapeutic options.

The transcription factor ETS1 in lymphomas: friend or foe?

ETS1 is a member of the ETS family of transcription factors, which contains many cancer genes. ETS1 gene is mapped at 11q24.3, a chromosomal region that is often the site of genomic rearrangements in hematological cancers. ETS1 is expressed in a variety of cells, including B and T lymphocytes. ETS1 is important in various biological processes such as development, differentiation, proliferation, apoptosis, migration and tissue remodeling. It acts as an oncogene controlling invasive and angiogenic behavior of malignant cells in multiple human cancers. In particular, ETS1 deregulation has been reported in diffuse large B-cell lymphoma, in Burkitt lymphoma and in Hodgkin lymphoma. Here, we summarize the function of ETS1 in normal cells, with a particular emphasis on lymphocytes, and its possible role as an oncogene or tumor suppressor gene in the different mature B cell lymphomas.

Ets and GATA transcription factors play a critical role in PMA-mediated repression of the ckβ promoter via the protein kinase C signaling pathway

BACKGROUND

Choline kinase is the most upstream enzyme in the CDP-choline pathway. It catalyzes the phosphorylation of choline to phosphorylcholine in the presence of ATP and Mg2+ during the biosynthesis of phosphatidylcholine, the major phospholipid in eukaryotic cell membranes. In humans, choline kinase (CK) is encoded by two separate genes, ckα and ckβ, which produce three isoforms, CKα1, CKα2, and CKβ. Previous studies have associated ckβ with muscle development; however, the molecular mechanism underlying the transcriptional regulation of ckβ has never been elucidated.

METHODOLOGY/PRINCIPAL FINDINGS

In this report, the distal promoter region of the ckβ gene was characterized. Mutational analysis of the promoter sequence and electrophoretic mobility shift assays (EMSA) showed that Ets and GATA transcription factors were essential for the repression of ckβ promoter activity. Supershift and chromatin immunoprecipitation (ChIP) assays further identified that GATA3 but not GATA2 was bound to the GATA site of ckβ promoter. In addition, phorbol-12-myristate-13-acetate (PMA) decreased ckβ promoter activity through Ets and GATA elements. PMA also decreased the ckβ mRNA and protein levels about 12 hours after the promoter activity was down-regulated. EMSA further revealed that PMA treatment increased the binding of both Ets and GATA transcription factors to their respective DNA elements. The PMA-mediated repressive effect was abolished by chronic PMA treatment and by treatment with the PKC inhibitor PKC412, but not the PKC inhibitor Go 6983, suggesting PKCε or PKCη as the PKC isozyme involved in the PMA-mediated repression of ckβ promoter. Further confirmation by using PKC isozyme specific inhibitors identified PKCε as the isozyme that mediated the PMA repression of ckβ promoter.

CONCLUSION/SIGNIFICANCE

These results demonstrate the participation of the PKC signaling pathway in the regulation of ckβ gene transcription by Ets and GATA transcription factors.

Understanding the role of ETS-mediated gene regulation in complex biological processes

Ets factors are members of one of the largest families of evolutionarily conserved transcription factors, regulating critical functions in normal cell homeostasis, which when perturbed contribute to tumor progression. The well-documented alterations in ETS factor expression and function during cancer progression result in pleiotropic effects manifested by the downstream effect on their target genes. Multiple ETS factors bind to the same regulatory sites present on target genes, suggesting redundant or competitive functions. The anti- and prometastatic signatures obtained by examining specific ETS regulatory networks will significantly improve our ability to accurately predict tumor progression and advance our understanding of gene regulation in cancer. Coordination of multiple ETS gene functions also mediates interactions between tumor and stromal cells and thus contributes to the cancer phenotype. As such, these new insights may provide a novel view of the ETS gene family as well as a focal point for studying the complex biological control involved in tumor progression. One of the goals of molecular biology is to elucidate the mechanisms that contribute to the development and progression of cancer. Such an understanding of the molecular basis of cancer will provide new possibilities for: (1) earlier detection, as well as better diagnosis and staging of disease; (2) detection of minimal residual disease recurrences and evaluation of response to therapy; (3) prevention; and (4) novel treatment strategies. Increased understanding of ETS-regulated biological pathways will directly impact these areas.

When Good Turns Bad: Regulation of Invasion and Metastasis by ErbB2 Receptor Tyrosine Kinase

Overexpression and activation of ErbB2 receptor tyrosine kinase in breast cancer is strongly linked to an aggressive disease with high potential for invasion and metastasis. In addition to inducing very aggressive, metastatic cancer, ErbB2 activation mediates processes such as increased cancer cell proliferation and survival and is needed for normal physiological activities, such as heart function and development of the nervous system. How does ErbB2 activation make cancer cells invasive and when? Comprehensive understanding of the cellular mechanisms leading to ErbB2-induced malignant processes is necessary for answering these questions. Here we present current knowledge about the invasion-promoting function of ErbB2 and the mechanisms involved in it. Obtaining detailed information about the "bad" behavior of ErbB2 can facilitate development of novel treatments against ErbB2-positive cancers.

Ets-1 global gene expression profile reveals associations with metabolism and oxidative stress in ovarian and breast cancers

Background

The Ets-1 proto-oncogene is frequently upregulated in cancer cells, with known involvement in cancer angiogenesis, metastasis, and more recently energy metabolism. In this study we have performed various bioinformatic analyses on existing microarray data to further clarify the role of Ets-1 in ovarian cancer, and validated these results with functional assays.

Methods

Functional pathway analyses were conducted on existing microarray data comparing 2008 and 2008-Ets1 ovarian cancer cells. Methods included over-representation analysis, functional class scoring and pathway topology, and network representations were visualized in Cytoscape. Oxidative stress regulation was examined in ovarian cancer cells by measuring protein expression and enzyme activity of glutathione peroxidases, as well as intracellular reactive oxygen species using dichlorofluorescin fluorescence. A stable Ets-1 knockdown MDA-MB-231 cell line was created using short hairpin RNA, and glycolytic dependence of these cells was measured following treatment with 2-deoxy-D-glucose and Hoechst nuclear staining to determine cell number. High-resolution respirometry was performed to measure changes in basal oxygen flux between MDA-MB-231 cells and MDA-Ets1KD variants.

Results

Enrichments in oxidoreductase activity and various metabolic pathways were observed upon integration of the different analyses, suggesting that Ets-1 is important in their regulation. As oxidative stress is closely associated with these pathways, we functionally validated our observations by showing that Ets-1 overexpression resulted in decreased reactive oxygen species with increased glutathione peroxidase expression and activity, thereby regulating cellular oxidative stress. To extend our findings to another cancer type, we developed an Ets-1 knockdown breast cancer cell model, which displayed decreased glycolytic dependence and increased oxygen consumption following Ets-1 knockdown confirming our earlier findings.

Conclusions

Collectively, this study confirms the important role of Ets-1 in the regulation of cancer energy metabolism in ovarian and breast cancers. Furthermore, Ets-1 is a key regulator of oxidative stress in ovarian cancer cells by mediating alterations in glutathione antioxidant capacity.

Multifunctional roles of urokinase plasminogen activator (uPA) in cancer stemness and chemoresistance of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is almost always lethal. One of the underlying reasons for this lethality is believed to be the presence of cancer stem cells (CSC), which impart chemoresistance and promote recurrence, but the mechanisms responsible are unclear. Recently the poor prognosis of PDAC has been correlated with increased expression of urokinase plasminogen activator (uPA). In the present study we examine the role of uPA in the generation of PDAC CSC. We observe a subset of cells identifiable as a side population (SP) when sorted by flow cytometry of MIA PaCa-2 and PANC-1 pancreatic cancer cells that possess the properties of CSC. A large fraction of these SP cells are CD44 and CD24 positive, are gemcitabine resistant, possess sphere-forming ability, and exhibit increased tumorigenicity, known characteristics of cancer stemness. Increased tumorigenicity and gemcitabine resistance decrease after suppression of uPA. We observe that uPA interacts directly with transcription factors LIM homeobox-2 (Lhx2), homeobox transcription factor A5 (HOXA5), and Hey to possibly promote cancer stemness. uPA regulates Lhx2 expression by suppressing expression of miR-124 and p53 expression by repressing its promoter by inactivating HOXA5. These results demonstrate that regulation of gene transcription by uPA contributes to cancer stemness and clinical lethality.

HGF-MET signals via the MLL-ETS2 complex in hepatocellular carcinoma

HGF signals through its cognate receptor, MET, to orchestrate diverse biological processes, including cell proliferation, cell fate specification, organogenesis, and epithelial-mesenchymal transition. Mixed-lineage leukemia (MLL), an epigenetic regulator, plays critical roles in cell fate, stem cell, and cell cycle decisions. Here, we describe a role for MLL in the HGF-MET signaling pathway. We found a shared phenotype among Mll(-/-), Hgf(-/-), and Met(-/-) mice with common cranial nerve XII (CNXII) outgrowth and myoblast migration defects. Phenotypic analysis demonstrated that MLL was required for HGF-induced invasion and metastatic growth of hepatocellular carcinoma cell lines. HGF-MET signaling resulted in the accumulation of ETS2, which interacted with MLL to transactivate MMP1 and MMP3. ChIP assays demonstrated that activation of the HGF-MET pathway resulted in increased occupancy of the MLL-ETS2 complex on MMP1 and MMP3 promoters, where MLL trimethylated histone H3 lysine 4 (H3K4), activating transcription. Our results present an epigenetic link between MLL and the HGF-MET signaling pathway, which may suggest new strategies for therapeutic intervention.

Overexpression of p16(INK4a) in urothelial carcinoma in situ is a marker for MAPK-mediated epithelial-mesenchymal transition but is not related to human papillomavirus infection

BACKGROUND

The role of human papillomavirus (HPV) in bladder carcinogenesis remains controversial. Overexpression of p16(INK4a), a surrogate marker for infection with oncogenic HPV in other tumours, has been described for urothelial carcinoma in situ (UCIS). Our goal was therefore to evaluate whether overexpression of p16(INK4a) is associated with HPV infection and to identify mechanisms of p16(INK4a) upregulation in UCIS.

MATERIALS AND METHODS

In 60 tissue specimens from a total of 45 patients (UCIS and controls), we performed p16(INK4a) immunohistochemistry followed by detection and subclassification of HPV DNA. In a subset of samples, we tested for gene amplification of p16(INK4a) applying fluorescence in situ hybridization (FISH). RAS/MAPK signalling and epithelial-mesenchymal transition (EMT) was assessed using immunohistochemistry. Finally, we transfected urothelial carcinoma cells with KRAS and examined the expression of p16(INK4a) as well as markers of EMT.

RESULTS

We found overexpression of p16(INK4a) in 92.6% of UCIS and in all cervical intraepithelial neoplasia (CIN) controls. In contrast, we detected high-risk HPV DNA in 80% of CIN, but none in UCIS. There was no gene amplification of p16(INK4a). High levels of phosphorylated kinases and urokinase plasminogen activator (uPA) and loss of membraneous E-cadherin were detected in UCIS. KRAS transfection of urothelial carcinoma cells led to upregulation of p16(INK4a) and uPA accompanied by loss of E-cadherin that could be inhibited by application of the kinase-inhibitor Sorafenib.

CONCLUSIONS

Our results show that overexpression of p16(INK4a) in UCIS is neither associated with HPV infection nor p16(INK4a) gene amplification but is a consequence of enhanced RAS/MAPK signalling that promotes EMT, possibly due to Sorafenib-sensitive paracrine secretion of the EMT activator uPA. These findings might open a novel therapeutic option for localized but aggressive urothelial cancer.

Interleukin enhancer-binding factor 3 promotes breast tumor progression by regulating sustained urokinase-type plasminogen activator expression

Sustained urokinase-type plasminogen activator (uPA) expression is detected in aggressive breast tumors. Although uPA can be transiently upregulated by diverse extracellular stimuli, sustained, but not transiently upregulated uPA expression contributes to breast cancer invasion/metastasis. Unfortunately, how sustained uPA expression is achieved in invasive/metastatic breast cancer cells is unknown. Here, we show that sustained and transiently upregulated uPA expression are regulated by distinct mechanisms. Using a collection of transcription factor-targeted small-interfering RNAs, we discovered that interleukin enhancer-binding factor 3 (ILF3) is required for sustained uPA expression. Two discrete mechanisms mediate ILF3 action. The first is that ILF3 activates uPA transcription by binding to the CTGTT sequence in the nucleotides -1004∼-1000 of the uPA promoter; the second is that ILF3 inhibits the processing of uPA mRNA-targeting primary microRNAs (pri-miRNAs). Knockdown of ILF3 led to significant reduction in in vitro cell growth/migration/invasion and in vivo breast tumor development. Importantly, immunohistochemistry (IHC) showed that nuclear ILF3, but not cytoplasmic ILF3 staining correlates with elevated uPA level and higher grades of human breast tumor specimens. Nuclear localization of ILF3 highlights the role of ILF3 in sustained uPA expression as a transcription activator and pri-miRNA processing blocker. In conclusion, this study shows that ILF3 promotes breast tumorigenicity by regulating sustained uPA expression.

Regression of intracranial aneurysms by simultaneous inhibition of nuclear factor-κB and Ets with chimeric decoy oligodeoxynucleotide treatment

BACKGROUND

Despite a high mortality and morbidity of subarachnoid hemorrhage due to an intracranial aneurysm (IA), there is no effective medical treatment to prevent the rupture of IAs. Recent studies have revealed the involvement of the transactivation of proinflammatory genes by nuclear factor-κB (NF-κB) and Ets-1 in the pathogenesis of IA formation and enlargement.

OBJECTIVE

To examine the regressive effect of chimeric decoy oligodeoxynucleotides (ODNs), which simultaneously inhibit NF-κB and Ets-1, on IA development in the rat model.

METHODS

One month after IA induction, rats were treated with NF-κB decoy ODNs or chimeric decoy ODNs. Size, media thickness, macrophage infiltration, and collagen biosynthesis in IA walls were analyzed in both groups.

RESULTS

The treatment with chimeric decoy ODNs decreased IA size and thickened IA walls of preexisting IAs induced in the rat model, although the treatment with NF-κB decoy ODNs failed to regress preexisting IAs. Chimeric decoy ODN-treated rats exhibited decreased expression of monocyte chemotactic protein-1 and macrophage infiltration in IA walls. In addition, decreased collagen biosynthesis in IA walls was ameliorated in the chimeric decoy ODN-treated group.

CONCLUSION

The results suggest the possibility of a minimally invasive molecular therapy targeting the inhibition of NF-κB and ets-1 for IAs in humans.

At the crossroads: EGFR and PTHrP signaling in cancer-mediated diseases of bone

The epidermal growth factor receptor is a well-established cancer therapeutic target due to its stimulation of proliferation, motility, and resistance to apoptosis. Recently, additional roles for the receptor have been identified in growth of metastases. Similar to development, metastatic spread requires signaling interactions between epithelial-derived tumor cells and mesenchymal derivatives of the microenvironment. This necessitates reactivation of developmental signaling molecules, including the hypercalcemia factor parathyroid hormone-related protein. This review covers the variations of epidermal growth factor receptor signaling in cancers that produce bone metastases, regulation of parathyroid hormone-related protein, and evidence that the two molecules drive cancer-mediated diseases of bone.

Analysis of gene networks in white adipose tissue development reveals a role for ETS2 in adipogenesis

Obesity is characterized by an expansion of white adipose tissue mass that results from an increase in the size and the number of adipocytes. However, the mechanisms responsible for the formation of adipocytes during development and the molecular mechanisms regulating their increase and maintenance in adulthood are poorly understood. Here, we report the use of leptin-luciferase BAC transgenic mice to track white adipose tissue (WAT) development and guide the isolation and molecular characterization of adipocytes during development using DNA microarrays. These data reveal distinct transcriptional programs that are regulated during murine WAT development in vivo. By using a de novo cis-regulatory motif discovery tool (FIRE), we identify two early gene clusters whose promoters show significant enrichment for NRF2/ETS transcription factor binding sites. We further demonstrate that Ets transcription factors, but not Nrf2, are regulated during early adipogenesis and that Ets2 is essential for the normal progression of the adipocyte differentiation program in vitro. These data identify ETS2 as a functionally important transcription factor in adipogenesis and its possible role in regulating adipose tissue mass in adults can now be tested. Our approach also provides the basis for elucidating the function of other gene networks during WAT development in vivo. Finally these data confirm that although gene expression during adipogenesis in vitro recapitulates many of the patterns of gene expression in vivo, there are additional developmental transitions in pre and post-natal adipose tissue that are not evident in cell culture systems.

ETS1 promotes chemoresistance and invasion of paclitaxel-resistant, hormone-refractory PC3 prostate cancer cells by up-regulating MDR1 and MMP9 expression

ETS1, which belongs to the ETS transcription factor family, plays important roles in diverse aspects of cancer such as drug resistance and metastasis. In the present study, we examined the functional roles of ETS1 in paclitaxel resistance and invasion using human prostate cancer PC3 cells and paclitaxel-resistant PC3PR cells established from PC3 cells. Our results showed that ETS1mRNA and protein expression was markedly up-regulated in paclitaxel-resistant PC3PR cells compared with paclitaxel-sensitive PC3 cells. The mRNA levels of MDR1 as well as MMP1, MMP3, MMP9 and uPA were positively correlated with that of ETS1. In PC3PR cells, silencing of ETS1 expression by siRNAs inhibited the activity of the MDR1 promoter containing ETS binding sites, reduced the mRNA and protein levels of MDR1 and suppressed paclitaxel resistance. Furthermore, ETS1 knockdown decreased secretion of MMP9 as well as its intracellular mRNA level, and dramatically inhibited invasion of PC3PR cells. Our results suggest that ETS1 promotes paclitaxel resistance and invasion in part by up-regulating MDR1 and MMP9 expression. Taken together, a novel therapeutic strategy targeting the ETS1 gene could be designed to overcome chemoresistance and metastasis of taxane-resistant, hormone-refractory prostate cancer.

c-Abl and Arg are activated in human primary melanomas, promote melanoma cell invasion via distinct pathways, and drive metastatic progression

Despite 35 years of clinical trials, there is little improvement in 1-year survival rates for patients with metastatic melanoma, and the disease is essentially untreatable if not cured surgically. The paucity of chemotherapeutic agents that are effective for treating metastatic melanoma indicates a dire need to develop new therapies. Here, we found a previously unrecognized role for c-Abl and Arg in melanoma progression. We demonstrate that the kinase activities of c-Abl and Arg are elevated in primary melanomas (60%), in a subset of benign nevi (33%) and in some human melanoma cell lines. Using siRNA and pharmacological approaches, we show that c-Abl/Arg activation is functionally relevant because it is requiredfor melanoma cell proliferation, survival and invasion. Significantly, we identify the mechanism by which activated c-Abl promotes melanoma invasion by showing that it transcriptionally upregulates matrix metalloproteinase-1 (MMP-1), and using rescue approaches we demonstrate that c-Abl promotes invasion through a STAT3 → MMP-1 pathway. Additionally, we show that c-Abl and Arg are not merely redundant, as active Arg drives invasion in a STAT3-independent manner, and upregulates MMP-3 and MT1-MMP, in addition to MMP-1. Most importantly, c-Abl and Arg not only promote in vitro processes important for melanoma progression, but also promote metastasis in vivo, as inhibition of c-Abl/Arg kinase activity with the c-Abl/Arg inhibitor, nilotinib, dramatically inhibits metastasis in a mouse model. Taken together, these data identify c-Abl and Arg as critical, novel, drug targets in metastatic melanoma, and indicate that nilotinib may be useful in preventing metastasis in patients with melanomas harboring active c-Abl and Arg.

Transcription factor AP-2α promotes EGF-dependent invasion of human trophoblast

The basic helix-span-helix transcription factor activating protein (AP)-2α is critically involved in cell-specific hormone expression of syncytializing human trophoblasts. Its role in invasive trophoblast differentiation, however, remains largely elusive. Using RT-PCR, Western blotting, and immunofluorescence of first-trimester placentae, we here show that AP-2α is expressed in extravillous trophoblasts (EVTs) both in situ and in vitro as well as in invasive trophoblast cell lines. Its protein expression was increased upon supplementation of epidermal growth factor (EGF) both in primary EVTs and trophoblastic SGHPL-5 cells. Gene silencing of AP-2α using small hairpin microRNA (shRNAmir) did not affect basal invasion of SGHPL-5 cells through Matrigel-coated filters but reduced EGF-stimulated invasion. Similarly, treatment of primary EVTs with AP-2α small interfering RNA decreased EGF-dependent invasion. Proliferation of SGHPL-5 cells and primary EVTs, measured by cumulative cell numbers and 5-bromo-2'-deoxyuridine labeling, respectively, were not affected on loss of AP-2α. EGF-dependent induction of matrix metalloproteinase (MMP)-2, pro- and active form of urokinase plasminogen activator, and chorionic gonadotropin (CG)-β was noticed in shRNAmir-control cells, whereas these genes were suppressed in EGF-treated shRNAmir-AP-2α cells. Similarly, EGF-stimulated MMP-2 and CGβ protein expression was reduced in AP-2α small interfering RNA-treated primary EVTs. Knockdown of AP-2α also decreased luciferase activity of the CGβ5 promoter in SGHPL-5 cells, which was compensated upon transient overexpression of AP-2α cDNA. In conclusion, we show that AP-2α expression positively affects human trophoblast invasion under EGF-stimulated conditions, likely by inducing critical invasion-promoting genes such MMP-2, urokinase plasminogen activator, and CG.

Ets1 blocks terminal differentiation of keratinocytes and induces expression of matrix metalloproteases and innate immune mediators

The transcription factor Ets1 is normally expressed in the proliferative layer of stratified epithelium, but expression of Ets1 is significantly upregulated in squamous cell carcinomas. How elevated levels of Ets1 impact tumor initiation and progression is not well understood. To determine the biological consequences of overexpression of Ets1, we developed a transgenic mouse model that allows induction of Ets1 expression in keratinocytes of stratified epithelium in a regulatable fashion. Induction of Ets1 during embryonic development results in a dramatic alteration in epidermal structure and function by suppressing the expression of multiple stratum corneum constituents, while at the same time inducing expression of EGF ligands, AP1 transcription factors and matrix metalloproteases. Interestingly, expression of certain immune-related genes, including defensins, chemokines and cytokines was increased as well, suggesting a possible role for immune dysregulation in the promotion of squamous dysplasia. Experiments using cultured mouse keratinocytes indicate that Ets1 can induce expression of some of these mediators in a cell-intrinsic fashion. Collectively, our data reveal that elevated expression of Ets1 has a much broader array of pro-tumorigenic effects on epithelial cells than previously appreciated.

Mechanisms associated with mitochondrial-generated reactive oxygen species in cancer

The mitochondria are unique cellular organelles that contain their own genome and, in conjunction with the nucleus, are able to transcribe and translate genes encoding components of the electron transport chain (ETC). To do so, the mitochondria must communicate with the nucleus via the production of reactive oxygen species (ROS) such as hydrogen peroxide (H2O2), which are produced as a byproduct of aerobic respiration within the mitochondria. Mitochondrial signaling is proposed to be altered in cancer cells, where the mitochondria are frequently found to harbor mutations within their genome and display altered functional characteristics leading to increased glycolysis. As signaling molecules, ROS oxidize and inhibit MAPK phosphatases resulting in enhanced proliferation and survival, an effect particularly advantageous to cancer cells. In terms of transcriptional regulation, ROS affect the phosphorylation, activation, oxidation, and DNA binding of transcription factors such as AP-1, NF-kappaB, p53, and HIF-1alpha, leading to changes in target gene expression. Increased ROS production by defective cancer cell mitochondria also results in the upregulation of the transcription factor Ets-1, a factor that has been increasingly associated with aggressive cancers.

Ets-1 regulates energy metabolism in cancer cells

Cancer cells predominantly utilize glycolysis for ATP production even in the presence of abundant oxygen, an environment that would normally result in energy production through oxidative phosphorylation. Although the molecular mechanism for this metabolic switch to aerobic glycolysis has not been fully elucidated, it is likely that mitochondrial damage to the electron transport chain and the resulting increased production of reactive oxygen species are significant driving forces. In this study, we have investigated the role of the transcription factor Ets-1 in the regulation of mitochondrial function and metabolism. Ets-1 was over-expressed using a stably-incorporated tetracycline-inducible expression vector in the ovarian cancer cell line 2008, which does not express detectable basal levels of Ets-1 protein. Microarray analysis of the effects of Ets-1 over-expression in these ovarian cancer cells shows that Ets-1 up-regulates key enzymes involved in glycolysis and associated feeder pathways, fatty acid metabolism, and antioxidant defense. In contrast, Ets-1 down-regulates genes involved in the citric acid cycle, electron transport chain, and mitochondrial proteins. At the functional level, we have found that Ets-1 expression is directly correlated with cellular oxygen consumption whereby increased expression causes decreased oxygen consumption. Ets-1 over-expression also caused increased sensitivity to glycolytic inhibitors, as well as growth inhibition in a glucose-depleted culture environment. Collectively our findings demonstrate that Ets-1 is involved in the regulation of cellular metabolism and response to oxidative stress in ovarian cancer cells.

Systemic administration of ribbon-type decoy oligodeoxynucleotide against nuclear factor κB and ets prevents abdominal aortic aneurysm in rat model

Currently, there is no effective clinical treatment to prevent abdominal aortic aneurysm (AAA). To develop a novel therapeutic approach, we modified decoy oligodeoxynucleotide (ODN) against nuclear factor κB (NFκB) and ets, to a ribbon-shaped circular structure without chemical modification, to increase its resistance to endonuclease for systemic administration. Intraperitoneal administration of ribbon-type decoy ODNs (R-ODNs) was performed in an elastase-induced rat AAA model. Fluorescent isothiocyanate (FITC)-labeled R-ODNs could be detected in macrophages migrating into the aneurysm wall, and NFκB and ets activity were simultaneously inhibited by chimeric R-ODN. Treatment with chimeric R-ODN significantly inhibited aortic dilatation, whereas conventional phosphorothioate decoy ODN failed to prevent aneurysm formation. Significant preservation of elastic fibers was observed with chimeric R-ODN, accompanied by a reduction of secretion of several proteases from macrophages. Activation of matrix metalloproteinase (MMP)-9 and MMP-12, but not MMP-2, was suppressed in the aneurysm wall by chimeric R-ODN, whereas recruitment of macrophages was not inhibited. Treatment with chimeric R-ODN also inhibited the secretion of cathepsin B and K from macrophages. Overall, the present study demonstrated that systemic administration of chimeric R-ODNs prevented aneurysm formation in a rat model. Further modification of the decoy strategy would provide a means of less invasive molecular therapy for human AAA.

Epidermal growth factor receptor-mediated regulation of urokinase plasminogen activator expression and glioblastoma invasion via C-SRC/MAPK/AP-1 signaling pathways

One of the major pathophysiological features of malignant astrocytomas is their ability to infiltrate surrounding brain tissue. The epidermal growth factor receptor (EGFR) and proteases are known to be overexpressed in glioblastomas (GBMs), but the interaction between the activation of the EGFR and urokinase plasminogen activator (uPA) in promoting astrocytic tumor invasion has not been fully elucidated. Here, we characterized the signal transduction pathway(s) by which EGF regulates uPA expression and promotes astrocytoma invasion. We show that EGFR activation and constitutively active EGFR vIII in GBM cell lines upregulate uPA expression. Small-molecule inhibitors of mitogen-activated protein kinase, tyrosine kinase, and small interfering RNA targeting c-Src blocked uPA upregulation. Similarly, mutations in the activator protein 1 binding site of the uPA promoter reduced EGF-induced increases in uPA promoter activity. Treatment of GBM cells with EGF increased in vitro cell invasion, and the invasive phenotype was attenuated by gene silencing of uPA using small interfering RNA and short hairpin RNA. In addition, uPA knockdown clones formed smaller well-circumscribed tumors than nontarget U1242 control cells in a xenograft GBM mouse model in vivo. In summary, these results suggest that c-Src, mitogen-activated protein kinase, and a composite activator protein 1 on the uPA promoter are responsible for EGF-induced uPA expression and GBM invasion.

Epidermal growth factor receptor signaling in nonsmall cell lung cancer

Epidermal growth factor is a 170-kd protein that binds to a specific tyrosine kinase receptor, epidermal growth factor receptor (EGFR), on the cell surface. EGFR function is dysregulated in various malignancies including nonsmall cell lung cancer (NSCLC) leading to activation of several signal transduction pathways including K-RAS, PIK3, and STAT3 and STAT5, that promote cell cycle progression, proliferation, invasion, angiogenesis, and inhibit apoptosis. EGFR overexpression is seen in a majority of cases of NSCLC, but its prognostic role is controversial. EGFR inhibitors currently undergoing clinical trials in NSCLC include monoclonal antibodies or small molecule tyrosine kinase inhibitors. The only EGFR inhibitor currently approved for the treatment of NSCLC is erlotinib, a small molecule tyrosine kinase inhibitor. Although women, nonsmokers, patients with adenocarcinoma and patients with Asian ethnicity seem to have better outcomes with erlotinib, the factors predictive for response to these agents are currently the focus of investigation.

Key signalling nodes in mammary gland development and cancer. Mitogen-activated protein kinase signalling in experimental models of breast cancer progression and in mammary gland development

Seven classes of mitogen-activated protein kinase (MAPK) intracellular signalling cascades exist, four of which are implicated in breast disease and function in mammary epithelial cells. These are the extracellular regulated kinase (ERK)1/2 pathway, the ERK5 pathway, the p38 pathway and the c-Jun N-terminal kinase (JNK) pathway. In some forms of human breast cancer and in many experimental models of breast cancer progression, signalling through the ERK1/2 pathway, in particular, has been implicated as being important. We review the influence of ERK1/2 activity on the organised three-dimensional association of mammary epithelial cells, and in models of breast cancer cell invasion. We assess the importance of epidermal growth factor receptor family signalling through ERK1/2 in models of breast cancer progression and the influence of ERK1/2 on its substrate, the oestrogen receptor, in this context. In parallel, we consider the importance of these MAPK-centred signalling cascades during the cycle of mammary gland development. Although less extensively studied, we highlight the instances of signalling through the p38, JNK and ERK5 pathways involved in breast cancer progression and mammary gland development.

Effect of bFGF on invasion of ovarian cancer cells through the regulation of Ets-1 and urokinase-type plasminogen activator

The aim of the study was to explore the role of basic fibroblast growth factor (bFGF) in ovarian cancer progression. This was done by investigating the effects of bFGF on both the secretion of urokinase-type plasminogen activator (uPA) and the invasion of tumor cells in SKOV(3) ovarian cancer cells. Human ovarian cancer cell line SKOV(3) was cultured in vitro. The expression of uPA gene and protein was induced in SKOV(3) cells; the impact of bFGF on the expression of uPA gene in SKOV(3) cells was studied by RT-PCR, and the impact of bFGF on the expression of uPA protein was tested by ELISA. Ets-1 antisense oligonucleotides were transfected into SKOV(3) cells by liposome protocol. The effects of bFGF on Ets-1 expression and the invasion ability of SKOV(3) cells were determined both before and after exposure to different concentrations of bFGF for 24 h. The expression of both uPA gene and protein was induced in SKOV(3) cells, p < 0.05. The expression of uPA was suppressed by Ets-1 antisense oligonucleotides in SKOV(3) cells, p < 0.05. The invasion ability of SKOV(3) cells was increased by 2.3-fold, and this effect was also suppressed by Ets-1 antisense oligonucleotides. bFGF can enhance the invasion ability of ovarian cancer cells in vitro by inducing the expression of uPA, and this effect is also regulated by the transcription factor Ets-1.

PLAUR polymorphisms and lung function in UK smokers

Background

We have previously identified Urokinase Plasminogen Activator Receptor (PLAUR) as an asthma susceptibility gene. In the current study we tested the hypothesis that PLAUR single nucleotide polymorphisms (SNPs) determine baseline lung function and contribute to the development of Chronic Obstructive Pulmonary Disease (COPD) in smokers.

Methods

25 PLAUR SNPs were genotyped in COPD subjects and individuals with smoking history (n = 992). Linear regression was used to determine the effects of polymorphism on baseline lung function (FEV₁, FEV₁/FVC) in all smokers. Genotype frequencies were compared in spirometry defined smoking controls (n = 176) versus COPD cases (n = 599) and COPD severity (GOLD stratification) using logistic regression.

Results

Five SNPs showed a significant association (p < 0.01) with baseline lung function; rs2302524(Lys220Arg) and rs2283628(intron 3) were associated with lower and higher FEV₁ respectively. rs740587(-22346), rs11668247(-20040) and rs344779(-3666) in the 5'region were associated with increased FEV₁/FVC ratio. rs740587 was also protective for COPD susceptibility and rs11668247 was protective for COPD severity although no allele dose relationship was apparent. Interestingly, several of these associations were driven by male smokers not females.

Conclusion

This study provides tentative evidence that the asthma associated gene PLAUR also influences baseline lung function in smokers. However the case-control analyses do not support the conclusion that PLAUR is a major COPD susceptibility gene in smokers. PLAUR is a key serine protease receptor involved in the generation of plasmin and has been implicated in airway remodelling.

Pten in stromal fibroblasts suppresses mammary epithelial tumours

The tumour stroma is believed to contribute to some of the most malignant characteristics of epithelial tumours. However, signalling between stromal and tumour cells is complex and remains poorly understood. Here we show that the genetic inactivation of Pten in stromal fibroblasts of mouse mammary glands accelerated the initiation, progression and malignant transformation of mammary epithelial tumours. This was associated with the massive remodelling of the extracellular matrix (ECM), innate immune cell infiltration and increased angiogenesis. Loss of Pten in stromal fibroblasts led to increased expression, phosphorylation (T72) and recruitment of Ets2 to target promoters known to be involved in these processes. Remarkably, Ets2 inactivation in Pten stroma-deleted tumours ameliorated disruption of the tumour microenvironment and was sufficient to decrease tumour growth and progression. Global gene expression profiling of mammary stromal cells identified a Pten-specific signature that was highly represented in the tumour stroma of patients with breast cancer. These findings identify the Pten-Ets2 axis as a critical stroma-specific signalling pathway that suppresses mammary epithelial tumours.

Binding sites for ETS family of transcription factors dominate the promoter regions of differentially expressed genes in abdominal aortic aneurysms

BACKGROUND

Previously, we identified 3274 distinct differentially expressed genes in abdominal aortic aneurysm (AAA) tissue compared with nonaneurysmal controls. As transcriptional control is responsible for these expression changes, we sought to find common transcriptional elements in the promoter regions of the differentially expressed genes.

METHODS AND RESULTS

We analyzed the up- and downregulated gene sets with Whole Genome rVISTA to determine the transcription factor (TF) binding sites overrepresented in the 5-kb promoter regions of the 3274 genes. The downregulated gene set yielded 144 TF binding sites that were overrepresented in the subset when compared with the entire genome. In contrast, the upregulated gene set yielded only 13 distinct overrepresented TF binding sites. Interestingly, as classified by TRANSFAC, 8 of the 13 TFs binding to these regions belong to the ETS family. Additionally, nuclear factor kB and its subunits p50 and p65 showed enrichment. Immunohistochemical analyses of 10 TFs from the upregulated set showed 9 to be present in AAA tissue. Based on gene ontology analysis of biological process categories of the upregulated target genes of enriched TFs, 10 TFs had enrichment in immune system process among their target genes.

CONCLUSIONS

Our genome-wide analysis provides further evidence of ETS and nuclear factor kB involvement in AAA. Additionally, our results provide novel insight for future studies aiming to dissect the pathogenesis of AAA and have uncovered potential therapeutic targets for AAA prevention.

Expression of the constitutively activated RelA/NF-kappaB in human astrocytic tumors and the in vitro implication in the regulation of urokinase-type plasminogen activator, migration, and invasion

Although malignant gliomas are highly invasive tumors, a characteristic that contributes to the commonly observed therapeutic failures and local disease recurrences, the molecular events that regulate invasion in these tumors remain poorly understood. Because the transcription factor RelA/NF-kappaB has been shown to regulate invasion during several cellular processes, we have examined immunohistochemically expression of the constitutively activated RelA/NF-kappaB in tissues obtained from 49 astrocytic tumors [8 diffuse astrocytomas, 9 anaplastic astrocytomas (AAs) and 32 glioblastomas (GBMs)]. In addition, we examined the in vitro effects of antisense oligonucleotides and curcumin on the expression and activation of RelA/NF-kappaB, urokinase-type plasminogen activator (u-PA) expression, migration, and invasion in the T98G glioma cell line. Expression of the constitutively activated RelA/NF-kappaB was observed in 2 (25%) of 8 cases of diffuse astrocytomas, 5 (55.6%) of 9 cases of AAs, and 30 (93.8%) of 32 cases of GBMs. This expression was significantly correlated with the malignant potential in astrocytic tumors (P < 0.001). Moreover, antisense oligonucleotides and curcumin inhibited phorbol-12-myristate-13-acetate (PMA)-induced RelA/NF-kappaB expression or activation (or both), down-regulated u-PA expression, and reduced the migration and invasive potentials of T98G glioma cells. Thus, the expression of constitutively activated RelA/NF-kappaB is associated with malignancy potential in astrocytic tumors and may play a critical role in the regulation of u-PA expression and invasiveness in gliomas. RelA/NF-kappaB may therefore be an intriguing candidate for studies aimed at understanding and prevention of the invasiveness of gliomas.

TOB1 is regulated by EGF-dependent HER2 and EGFR signaling, is highly phosphorylated, and indicates poor prognosis in node-negative breast cancer

Clinical and animal studies have shown that coexpression of the receptor tyrosine kinases HER2 and epidermal growth factor (EGF) receptor (EGFR) indicates a highly metastatic phenotype of breast cancer. In a cellular model of this phenotype using differential gene expression analysis, we identified TOB1 to be up-regulated depending on EGF stimulation and transduction through phosphorylation of HER2 tyrosine 1248. mRNA expression analysis of breast cancers from a cohort of node-negative patients showed significantly shortened distant metastasis-free survival for patients with high TOB1 expression. In subsequent tissue microarray studies of 725 clinical samples, high HER2 and EGF protein levels were significantly correlated with TOB1 expression in breast cancer, whereas EGFR and EGF levels correlated with TOB1 phosphorylation. We did not observe a correlation between TOB1 expression and cyclin D1, which was previously suggested to mediate the antiproliferative effect of unphosphorylated TOB1. A positive correlation of TOB1 phosphorylation status with proliferation marker Ki67 suggests that elevated TOB1 phosphorylation might abrogate the antiproliferative effect of TOB1 in breast cancer. This suggests a new regulatory role for TOB1 in cancer progression with particular significance in HER2- and/or EGFR-positive breast cancers.