The transcription factor Egr1 is a direct regulator of multiple tumor suppressors including TGFbeta1, PTEN, p53, and fibronectin

EGR1 as a potential marker of prognosis in extranodal NK/T-cell lymphoma

Extranodal natural killer T-cell lymphoma (ENKTL) is an aggressive malignancy with a dismal prognosis. In the present study, gene expression profiling was performed to provide more information on ENKTL molecular signature and offer a rationale for further investigation of prognostic markers in ENKTL. NanoString nCounter Analysis encompassing 133 target genes was used to compare gene expression levels of 43 ENKTL tumor samples. The majority of the patients were under 60 years of age (79.1%); 32 (74.4%) patients had nasal type ENKTL and 23 patients (53.5%) had intermediate/high risk ENKTL based on the prognostic index for natural killer cell lymphoma (PINK). The median follow-up was 15.9 months and the median overall survival (OS) was 16.1 months (95% CI 13.0-69.8). EGR1 upregulation was consistently identified in the localized stage with a low risk of prognostic index based on the PINK. Among the six significantly relevant genes for EGR1 expression, high expression levels of genes, including CD59, GAS1, CXCR7, and RAMP3, were associated with a good survival prognosis. The in vitro test showed EGR1 modulated the transcriptional activity of the target genes including CD59, GAS1, CXCR7, and RAMP3. Downregulation of EGR1 and its target genes significantly inhibited apoptosis and decreased chemosensitivity and attenuated radiation-induced apoptosis. The findings showed EGR1 may be a candidate for prognostic markers in ENKTL. Considerable additional characterization may be necessary to fully understand EGR1.

Differently sized drug-loaded mesoporous silica nanoparticles elicit differential gene expression in MCF-7 cancer cells

Aim: This study investigates the effects of different sized unmodified and chemo-responsive mesoporous silica nanocarriers on MCF-7 cancer cells. Materials & methods: Unmodified and thiol-functionalized large and small-sized mesoporous MCM-41 silica nanoparticles prepared using templated sol-gel process were characterized for their physicochemical properties and in vitro and in vivo anticancer efficacy. Microarray analysis was carried out to assess their differential effect on gene expression. Results: Thiol-functionalized nanoparticles displayed chemo responsive release and greater cytotoxicity to cancer cells when compared with unmodified carriers. Microarray studies showed distinct differences in genes differentially regulated by sMCM-41and lMCM-41 carriers when compared with the free drug. Conclusion: The small chemo-responsive carrier was more effective in suppressing oncogenes and genes involved in proliferation, invasion and survival while the large carrier mainly altered membrane-associated pathways.

BCL9/BCL9L promotes tumorigenicity through immune-dependent and independent mechanisms in triple negative breast cancer

Treatment of patients with triple-negative breast cancer (TNBC) has been challenging due to a lack of well-defined molecular targets. The Wnt/β-catenin pathway is known to be activated in many TNBC patients and BCL9 and BCL9L are important transcriptional co-activators of β-catenin, but whether inhibition of BCL9/BCL9L can suppress TNBC growth and the underlying mechanism are not fully understood. Here we demonstrate that the expression of BCL9 and BCL9L is directly correlated with malignancy in TNBC patient tumors and that BCL9 and BCL9L promote tumor cell growth, cell migration and metastasis in TNBC models. Mechanistically, we found that BCL9/BCL9L promotes tumorigenicity through both the Wnt and TGF-β pathways. Besides, BCL9/BCL9L expression inversely correlates with CD8⁺ T cell infiltration in TNBC and BCL9/BCL9L inhibits the infiltration of CD8⁺ T cells in the tumor microenvironment. hsBCL9_CT-24, an inhibitor of BCL9/β-catenin peptides, promotes intratumoral infiltration of cytotoxic T cells, reducing regulatory T cells (Treg) and increasing dendritic cells (DCs). Inhibition of BCL9/BCL9L and TGF-β suppresses activity of Treg. TGF-β signaling increases tumor infiltration of cytotoxic CD8⁺ T cells. In accordance, genetic or pharmacological inhibition of BCL9/BCL9L synergizes with PD-1/L1 antibodies to inhibit tumor growth. In summary, these results suggest that targeting BCL9/BCL9L has a direct anti-tumor effect and also unleashes an anti-cancer immune response through inhibition of both Wnt and TGF-β signaling, suggesting a viable therapeutic approach for TNBC treatment.

HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) versus adult T-cell leukemia/lymphoma (ATLL)

Objectives

Human T cell leukemia virus-1 (HTLV-1) infection may lead to one or both diseases including HTLV-1-associated myelopathy/tropical spastic paraparesis (HAM/TSP) or adult T cell leukemia lymphoma (ATLL). The complete interactions of the virus with host cells in both diseases is yet to be determined. This study aims to construct an interaction network for distinct signaling pathways in these diseases based on finding differentially expressed genes (DEGs) between HAM/TSP and ATLL.

Results

We identified 57 hub genes with higher criteria scores in the primary protein–protein interaction network (PPIN). The ontology-based enrichment analysis revealed following important terms: positive regulation of transcription from RNA polymerase II promoter, positive regulation of transcription from RNA polymerase II promoter involved in meiotic cell cycle and positive regulation of transcription from RNA polymerase II promoter by histone modification. The upregulated genes TNF, PIK3R1, HGF, NFKBIA, CTNNB1, ESR1, SMAD2, PPARG and downregulated genes VEGFA, TLR2, STAT3, TLR4, TP53, CHUK, SERPINE1, CREB1 and BRCA1 were commonly observed in all the three enriched terms in HAM/TSP vs. ATLL. The constructed interaction network was then visualized inside a mirrored map of signaling pathways for ATLL and HAM/TSP, so that the functions of hub genes were specified in both diseases.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-021-05521-y.

An integrated epigenomic-transcriptomic landscape of lung cancer reveals novel methylation driver genes of diagnostic and therapeutic relevance

Background: Aberrant DNA methylation occurs commonly during carcinogenesis and is of clinical value in human cancers. However, knowledge of the impact of DNA methylation changes on lung carcinogenesis and progression remains limited.

Methods: Genome-wide DNA methylation profiles were surveyed in 18 pairs of tumors and adjacent normal tissues from non-small cell lung cancer (NSCLC) patients using Reduced Representation Bisulfite Sequencing (RRBS). An integrated epigenomic-transcriptomic landscape of lung cancer was depicted using the multi-omics data integration method.

Results: We discovered a large number of hypermethylation events pre-marked by poised promoter in embryonic stem cells, being a hallmark of lung cancer. These hypermethylation events showed a high conservation across cancer types. Eight novel driver genes with aberrant methylation (e.g., PCDH17 and IRX1) were identified by integrated analysis of DNA methylome and transcriptome data. Methylation level of the eight genes measured by pyrosequencing can distinguish NSCLC patients from lung tissues with high sensitivity and specificity in an independent cohort. Their tumor-suppressive roles were further experimentally validated in lung cancer cells, which depend on promoter hypermethylation. Similarly, 13 methylation-driven ncRNAs (including 8 lncRNAs and 5 miRNAs) were identified, some of which were co-regulated with their host genes by the same promoter hypermethylation. Finally, by analyzing the transcription factor (TF) binding motifs, we uncovered sets of TFs driving the expression of epigenetically regulated genes and highlighted the epigenetic regulation of gene expression of TCF21 through DNA methylation of EGR1 binding motifs.

Conclusions: We discovered several novel methylation driver genes of diagnostic and therapeutic relevance in lung cancer. Our findings revealed that DNA methylation in TF binding motifs regulates target gene expression by affecting the binding ability of TFs. Our study also provides a valuable epigenetic resource for identifying DNA methylation-based diagnostic biomarkers, developing cancer drugs for epigenetic therapy and studying cancer pathogenesis.

EGR-1 plays a protective role in AMPK inhibitor compound C-induced apoptosis through ROS-induced ERK activation in skin cancer cells

Skin cancer is caused by abnormal proliferation, gene regulation and mutation of epidermis cells. Compound C is commonly used as an inhibitor of AMP-activated protein kinase (AMPK), which serves as an energy sensor in cells. Recently, compound C has been reported to induce apoptotic and autophagic death in various skin cancer cell lines via an AMPK-independent pathway. However, the signaling pathways activated in compound C-treated cancer cells remain unclear. The present oligodeoxynucleotide-based microarray screening assay showed that the mRNA expression of the zinc-finger transcription factor early growth response-1 (EGR-1), which helps regulate cell cycle progression and cell survival, was significantly upregulated in compound C-treated skin cancer cells. Compound C was demonstrated to induce EGR-1 mRNA and protein expression in a time and dose-dependent manner. Confocal imaging showed that compound C-induced EGR-1 protein expression was localized in the nucleus. Compound C was demonstrated to activate extracellular signal-regulated kinase (ERK) phosphorylation. Inhibition of this compound C-induced ERK phosphorylation downregulated the mRNA and protein expression of EGR-1. In addition, removal of compound C-induced reactive oxygen species (ROS) not only decreased ERK phosphorylation, but also inhibited compound C-induced EGR-1 expression. A functional assay showed that knock down of EGR-1 expression in cancer cells decreased the survival rate while also increasing caspase-3 activity and apoptotic marker expression after compound C treatment. However, no difference in autophagy marker light chain 3-II protein expression was observed between compound C-treated control cells and EGR-1-knockdown cells. Thus, it was concluded that that EGR-1 may antagonize compound C-induced apoptosis but not compound C-induced autophagy through the ROS-mediated ERK activation pathway.

Galectin-1-RNA interaction map reveals potential regulatory roles in angiogenesis

Hyperactive angiogenesis contributes to the immunosuppressive microenvironment important for immunotherapy. Galectin-1, encoded by LGALS1, can trigger the vascular signaling programs and mediate the anti-angiogenic treatment response. However, the mechanism through which galectin-1 regulates angiogenesis is poorly understood. It has been suggested that galectin-1 may associate with mRNAs in cells. This study applied the iRIP-seq methodology to study the potential role of galectin-1 as an RNA-binding protein. We found that galectin-1 interacts with a large number of mRNAs, with a preference for binding near stop codons and a preference for UGCA/UGGA and GAGCAG as binding motifs. Galectin-1 binds to the mRNAs of angiogenesis-associated genes including VEGFA, EGR1, and LAMA5, suggesting that galectin-1 may regulate angiogenesis via its mRNA-binding activity. We further show that shLGALS1 inhibits capillary tube formation in an in vitro angiogenesis assay and alters the expression levels of several galectin-1-bound angiogenesis-associated mRNAs. These results uncover a previously unrecognized mRNA-binding activity of galectin-1.

EGR1/GADD45α Activation by ROS of Non-Thermal Plasma Mediates Cell Death in Thyroid Carcinoma

Simple Summary

Recent studies have identified new anti-cancer mechanisms of nonthermal plasma (NTP) in several cancers. However, the molecular mechanisms underlying its therapeutic effect on thyroid cancer have not been elucidated. The objective of this study was to understand the anticancer effects of NTP-activated medium (NTPAM) on thyroid cancer cells and elucidate the signaling mechanisms responsible for NTPAM-induced thyroid cancer cell death.

Abstract

(1) Background: Nonthermal plasma (NTP) induces cell death in various types of cancer cells, providing a promising alternative treatment strategy. Although recent studies have identified new mechanisms of NTP in several cancers, the molecular mechanisms underlying its therapeutic effect on thyroid cancer (THCA) have not been elucidated. (2) Methods: To investigate the mechanism of NTP-induced cell death, THCA cell lines were treated with NTP-activated medium -(NTPAM), and gene expression profiles were evaluated using RNA sequencing. (3) Results: NTPAM upregulated the gene expression of early growth response 1 (EGR1). NTPAM-induced THCA cell death was enhanced by EGR1 overexpression, whereas EGR1 small interfering RNA had the opposite effect. NTPAM-derived reactive oxygen species (ROS) affected EGR1 expression and apoptotic cell death in THCA. NTPAM also induced the gene expression of growth arrest and regulation of DNA damage-inducible 45α (GADD45A) gene, and EGR1 regulated GADD45A through direct binding to its promoter. In xenograft in vivo tumor models, NTPAM inhibited tumor progression of THCA by increasing EGR1 levels. (4) Conclusions: Our findings suggest that NTPAM induces apoptotic cell death in THCA through a novel mechanism by which NTPAM-induced ROS activates EGR1/GADD45α signaling. Furthermore, our data provide evidence that the regulation of the EGR1/GADD45α axis can be a novel strategy for the treatment of THCA.

DNA methylome profiling of circulating tumor cells in lung cancer at single base-pair resolution

DNA methylation plays a pivotal role in regulating cellular processes, and altered DNA methylation pattern is a general hallmark of cancer. However, DNA methylome in circulating tumor cells (CTCs) is still a mystery due to the lack of proper analytical techniques. We introduced an efficient workflow, LCM-µWGBS, which can efficiently profile the DNA methylation of microdissected CTC samples. LCM-µWGBS combines the laser capture microdissection (LCM)-based CTC capture method and whole-genome bisulfite sequencing in very small CTC population (µWGBS) to gain insight into the DNA methylation landscape of CTCs. We herein profiled the DNA methylome of CTCs from lung cancer patients. Deriving from a comprehensive analysis of CTC methylome, a unique "CTC DNA methylation signature" that is distinct from primary lung cancer tissues was identified. Further analysis showed that promoter hypermethylation of epithelial genes is a hallmark of stable epithelial-mesenchymal transition process. Moreover, it has been suggested that CTCs are endowed with a stemness-related feature during dissemination and metastasis. This work constitutes a unique DNA methylation analysis of CTCs at single base-pair resolution, which might facilitate to propose noninvasive CTC DNA methylation biomarkers contributing to clinical diagnosis.

Ring finger protein 2 promotes colorectal cancer progression by suppressing early growth response 1

Ring finger protein 2 (RNF2) is an important component of polycomb repressive complex 1. RNF2 is upregulated in many kinds of tumors, and elevated RNF2 expression is associated with a poor prognosis in certain cancers. To assess the function of RNF2 in colorectal cancer, we examined RNF2 protein levels in 313 paired colorectal cancer tissues and adjacent normal tissues. We then analyzed the association of RNF2 expression with the patients’ clinicopathologic features and prognoses. RNF2 expression was upregulated in colorectal cancer tissues and was associated with the tumor differentiation status, tumor stage and prognosis. In colorectal cancer cell lines, downregulation of RNF2 inhibited cell proliferation and induced apoptosis. Gene microarray analysis revealed that early growth response 1 (EGR1) was upregulated in RNF2-knockdown cells. Knocking down EGR1 partially reversed the inhibition of cell proliferation and the induction of apoptosis in RNF2-knockdown cells. RNF2 was enriched at the EGR1 promoter, where it mono-ubiquitinated histone H2A, thereby inhibiting EGR1 expression. These results indicate that RNF2 is oncogenic in colorectal cancer and may promote disease progression by inhibiting EGR1 expression. RNF2 is thus a potential prognostic marker and therapeutic target in colorectal cancer.

Transforming Growth Factor-β and the Renin-Angiotensin System in Syndromic Thoracic Aortic Aneurysms: Implications for Treatment

Thoracic aortic aneurysms (TAAs) are permanent pathological dilatations of the thoracic aorta, which can lead to life-threatening complications, such as aortic dissection and rupture. TAAs frequently occur in a syndromic form in individuals with an underlying genetic predisposition, such as Marfan syndrome (MFS) and Loeys-Dietz syndrome (LDS). Increasing evidence supports an important role for transforming growth factor-β (TGF-β) and the renin-angiotensin system (RAS) in TAA pathology. Eventually, most patients with syndromic TAAs require surgical intervention, as the ability of present medical treatment to attenuate aneurysm growth is limited. Therefore, more effective medical treatment options are urgently needed. Numerous clinical trials investigated the therapeutic potential of angiotensin receptor blockers (ARBs) and β-blockers in patients suffering from syndromic TAAs. This review highlights the contribution of TGF-β signaling, RAS, and impaired mechanosensing abilities of aortic VSMCs in TAA formation. Furthermore, it critically discusses the most recent clinical evidence regarding the possible therapeutic benefit of ARBs and β-blockers in syndromic TAA patients and provides future research perspectives and therapeutic implications.

Detection of tmprss2-erg and tmprss2-egr1 gene fusion in prostate cancer from a Chinese population

Background

TMPRSS2: ETS gene fusion occurs recurrently in a high proportion of prostate cancer (PCa) patients in Western countries. However, for Chinese PCa patients, no solid conclusion could be drawn from the present studies, as the results varied considerably between the limited reports.

Results

In this study, we evaluated the prevalence of such gene rearrangements in a small number of Chinese PCa patients and discovered that 6 out of 27 (22.2%) were found to harbor the TMPRSS2: ERG fusion, the ratio was much lower than that in Western countries. Furthermore, we first identified TMPRSS2: EGR1 gene fusion, suggesting other chromosome rearrangements besides ETS gene family harbor in prostate cancer. The hybrid transcript was predicted to encode a truncated EGR1 protein by ORF finder, which might play a key role in prostate cancer.

Conclusions

We reported that the total occurrence rate of TMPRSS2: ERG fusion gene in this small group of Chinese patients was lower than the reported frequencies in European descent patients but comparable to other reported frequencies in Asian populations. The occurrence of TMPRSS2: EGR1 gene fusion suggested other chromosome rearrangements in prostate cancer.

Photochemotherapy Induces Interferon Type III Expression via STING Pathway

DNA-damaging cancer therapies induce interferon expression and stimulate the immune system, promoting therapy responses. The immune-activating STING (Stimulator of Interferon Genes) pathway is induced when DNA or double-stranded RNA (dsRNA) is detected in the cell cytoplasm, which can be caused by viral infection or by DNA damage following chemo- or radiotherapy. Here, we investigated the responses of cutaneous T-cell lymphoma (CTCL) cells to the clinically applied DNA crosslinking photochemotherapy (combination of 8–methoxypsoralen and UVA light; 8–MOP + UVA). We showed that this treatment evokes interferon expression and that the type III interferon IFNL1 is the major cytokine induced. IFNL1 upregulation is dependent on STING and on the cytoplasmic DNA sensor cyclic GMP-AMP synthase (cGAS). Furthermore, 8–MOP + UVA treatment induced the expression of genes in pathways involved in response to the tumor necrosis factor, innate immune system and acute inflammatory response. Notably, a subset of these genes was under control of the STING–IFNL1 pathway. In conclusion, our data connected DNA damage with immune system activation via the STING pathway and contributed to a better understanding of the effectiveness of photochemotherapy.

Environmental Epigenetics of Diesel Particulate Matter Toxicogenomics

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by disruptions in social communication and behavioral flexibility. Both genetic and environmental factors contribute to ASD risk. Epidemiologic studies indicate that roadway vehicle exhaust and in utero exposure to diesel particulate matter (DPM) are associated with ASD. Using the Comparative Toxicogenomics Database (CTD), we identified genes connected to DPM exposure and ASD, extracted the known enhancers/promoters of the identified genes, and integrated this with Assay for Transposase Accessible Chromatin (ATAC-seq) data from DPM-exposed human neural progenitor cells. Enhancer/promoter elements with significantly different chromosome accessibility revealed enriched DNA sequence motifs with transcription factor binding sites for EGR1. Variant extraction for linkage disequilibrium blocks of these regions followed by analysis through Genome Wide Association Studies (GWAS) revealed multiple neurological trait associations including exploratory eye movement and brain volume measurement. This approach highlights the effects of pollution on the regulatory regions of genes implicated in ASD by genetic studies, indicating convergence of genetic and environmental factors on molecular networks that contribute to ASD. Integration of publicly available data from the CTD, cell culture exposure studies, and phenotypic genetics synergize extensive evidence of chemical exposures on gene regulation for altered brain development.

EZH2 overexpression dampens tumor-suppressive signals via an EGR1 silencer to drive breast tumorigenesis

The mechanism underlying EZH2 overexpression in breast cancer and its involvement in tumorigenesis remain poorly understood. In this study, we developed an approach to systematically identify the trans-acting factors regulating the EZH2 expression, and identified more than 20 such factors. We revealed reciprocal regulation of early growth response 1 (EGR1) and EZH2: EGR1 activates the expression of EZH2, and EZH2 represses EGR1 expression. Using CRISPR-mediated genome/epigenome editing, we demonstrated that EHZ2 represses EGR1 expression through a silencer downstream of the EGR1 gene. Deletion of the EGR1 silencer resulted in reduced cell growth, invasion, tumorigenicity of breast cancer cells, and extensive changes in gene expression, such as upregulation of GADD45, DDIT3, and RND1; and downregulation of genes encoding cholesterol biosynthesis pathway enzymes. We hypothesize that EZH2/PRC2 acts as a "brake" for EGR1 expression by targeting the EGR1 silencer, and EZH2 overexpression dampens tumor-suppressive signals mediated by EGR1 to drive breast tumorigenesis.

MiR-125b-2-3p associates with prognosis of ccRCC through promoting tumor metastasis via targeting EGR1

Clear cell renal cell carcinoma (ccRCC) is an aggressive tumor with frequent metastatic rate. In order to explore the mechanisms, we determined the roles of miR-125b-2-3p in metastatic ccRCC progression. In the study, both clinical and experimental evidences supported the critical role of miR-125b-2-3p in accelerating ccRCC metastasis. Elevated miR-125b-2-3p expression correlated with lymphatic invasion, distant metastasis and poor survival. Functional study showed that high miR-125b-2-3p expression significantly increased ccRCC cell migration in vitro and lung metastasis in vivo. Furthermore, we demonstrated that miR-125b-2-3p directly targeted EGR1, and miR-125b-2-3p accelerated ccRCC cell migration through down-regulating EGR1. Taken together, this study demonstrated that miR-125b-2-3p associates with ccRCC prognosis via promoting tumor metastasis through targeting EGR1.

Cellular and molecular events of inflammation induced transdifferentiation (EMT) and regeneration (MET) in mesenteric mesothelial cells

In this review we summarize the cellular and molecular events of inflammation induced epithelial-to-mesenchymal (EMT) and mesothelial-to-macrophage transition (MET) during regeneration. Since the receptor transmits the environmental stimulus, downregulating or upregulating the process on an epigenetic level, the intracellular localization of receptors (signaling organelles: early endosomes or lysosomal degradation: late endosomes) plays a crucial role in the signaling events regulating inflammation and regeneration. Therefore, we focused on the internalization of the receptors as well as the intracellular compartmentalization of signaling molecules during EMT and MET. The review draws the reader's attention to the plasticity of mesothelial cells and supports the idea that during inflammation an ambient macrophage population might derive from mesothelial cells.

MicroRNA-7 targets T-Box 2 to inhibit epithelial-mesenchymal transition and invasiveness in glioblastoma multiforme

The dysregulation of microRNA expression in cancer has been associated with the epithelial-mesenchymal transition (EMT) that triggers invasive ability and increases therapeutic resistance. Here, we determined the microRNA expression profile of seven tumor tissues from patients with glioblastoma multiforme (GBM) by use of microRNA array analysis. We discovered that microRNA-7 (miR-7) is consistently downregulated in all tumor samples. Using the microRNA.org algorithm, the T-box 2 gene (TBX2) was identified as a candidate gene targeted by miR-7. In contrast to miR-7, TBX2 had an increased expression in GBM tumors and was linked to poor prognosis. We confirmed that TBX2 mRNA and protein production are significantly repressed by overexpressing miR-7 in GBM cells in vitro. The reporter assay showed that miR-7 significantly represses the signal from luciferase with the 3' UTR of TBX2. Furthermore, TBX2 overexpression decreased E-cadherin expression and increased Vimentin expression, causing an increasing number of invaded cells in the invasion assay, as well as pulmonary metastasis in vivo. Our findings demonstrated that overexpression of TBX2 in GBM tumors via the downregulation of miR-7 leads to EMT induction and increased cell invasion.

Calcium Channel Blockers Impair the Antitumor Activity of Anti-CD20 Monoclonal Antibodies by Blocking EGR-1 Induction

Direct cell death induction, in addition to immune-effector cell-mediated mechanisms, is one of the key mechanisms of action of anti-CD20 antibodies, and yet the signaling pathways implicated remain poorly investigated. Here we show that the transcription factor EGR-1 is rapidly induced by anti-CD20 antibodies and is a key mediator for CD20-induced cell death. EGR-1 induction results from an increased calcium influx induced by anti-CD20 antibodies. We show that both rituximab and obinutuzumab induce calcium influx, albeit through different mechanisms, and this influx is crucial for cell death induction. Inhibition of the calcium flux with calcium channel blockers (CCB) abolished EGR-1 induction and impaired the efficacy of anti-CD20 antibodies in preclinical in vitro and in vivo models. Finally, we investigated the impact of CCBs in patients treated with anti-CD20 antibodies included in the clinical trials GOYA and REMARC, and found that patients simultaneously receiving CCBs and anti-CD20 therapy have a shorter progression-free survival and overall survival. These results reveal EGR-1 as a key mediator of the direct cytotoxic activity of anti-CD20 antibodies and provide a rationale to evaluate EGR-1 expression as a new biomarker to predict response to anti-CD20 treatment. In addition, our findings show that calcium influx is required for anti-CD20-mediated tumor cell death and suggest that simultaneous administration of calcium channel blocking agents could be deleterious in patients receiving anti-CD20-based immunotherapy.

Identification of atheroprone shear stress responsive regulatory elements in endothelial cells

AIMS

Oscillatory shear stress (OSS) is an atheroprone haemodynamic force that occurs in areas of vessel irregularities and is implicated in the pathogenesis of atherosclerosis. Changes in signalling and transcriptional programme in response to OSS have been vigorously studied; however, the underlying changes in the chromatin landscape controlling transcription remain to be elucidated. Here, we investigated the changes in the regulatory element (RE) landscape of endothelial cells under atheroprone OSS conditions in an in vitro model.

METHODS AND RESULTS

Analyses of H3K27ac chromatin immunoprecipitation-Seq enrichment and RNA-Seq in primary human umbilical vein endothelial cells 6 h after onset of OSS identified 2806 differential responsive REs and 33 differentially expressed genes compared with control cells kept under static conditions. Furthermore, gene ontology analyses of putative RE-associated genes uncovered enrichment of WNT/HIPPO pathway and cytoskeleton reorganization signatures. Transcription factor (TF) binding motif analysis within RE sequences identified over-representation of ETS, Zinc finger, and activator protein 1 TF families that regulate cell cycle, proliferation, and apoptosis, implicating them in the development of atherosclerosis. Importantly, we confirmed the activation of EGR1 as well as the YAP/TAZ complex early (6 h) after onset of OSS in both cultured human vein and artery endothelial cells and, by undertaking luciferase assays, functionally verified their role in RE activation in response to OSS.

CONCLUSIONS

Based on the identification and verification of specific responsive REs early upon OSS exposure, we propose an expanded mechanism of how OSS might contribute to the development of atherosclerosis.

Expression and prognostic value of the transcription factors EGR1 and EGR3 in gliomas

Most glioblastoma patients have a dismal prognosis, although some survive several years. However, only few biomarkers are available to predict the disease course. EGR1 and EGR3 have been linked to glioblastoma stemness and tumour progression, and this study aimed to investigate their spatial expression and prognostic value in gliomas. Overall 207 gliomas including 190 glioblastomas were EGR1/EGR3 immunostained and quantified. A cohort of 21 glioblastomas with high P53 expression and available tissue from core and periphery was stained with double-immunofluorescence (P53-EGR1 and P53-EGR3) and quantified.EGR1 expression increased with WHO-grade, and declined by 18.9% in the tumour periphery vs. core (P = 0.01), while EGR3 expression increased by 13.8% in the periphery vs. core (P = 0.04). In patients with high EGR1 expression, 83% had methylated MGMT-promoters, while all patients with low EGR1 expression had un-methylated MGMT-promoters. High EGR3 expression in MGMT-methylated patients was associated with poor survival (HR = 1.98; 95%CI 1.22–3.22; P = 0.006), while EGR1 high/EGR3 high, was associated with poor survival vs. EGR1 high/EGR3 low (HR = 2.11; 95%CI 1.25–3.56; P = 0.005). EGR1 did not show prognostic value, but could be involved in MGMT-methylation. Importantly, EGR3 may be implicated in cell migration, while its expression levels seem to be prognostic in MGMT-methylated patients.

MNK1 signaling induces an ANGPTL4-mediated gene signature to drive melanoma progression

The BRAFV600E mutation occurs in more than 50% of cutaneous melanomas, and results in the constitutive activation of the mitogen-activated protein kinases (MAPK) pathway. MAP kinase-interacting serine/threonine-protein kinase 1 and 2 (MNK1/2) are downstream effectors of the activated MAPK pathway, and important molecular targets in invasive and metastatic cancer. Despite the well-known role of MNK1 in regulating mRNA translation, little is known concerning the impact of its aberrant activation on gene transcription. Here, we show that changes in the activity, or abundance, of MNK1 result in changes in the expression of pro-oncogenic and pro-invasive genes. Among the MNK1-upregulated genes, we identify Angiopoietin-like 4 (ANGPTL4), which in turn promotes an invasive phenotype via its ability to induce the expression of matrix metalloproteinases (MMPs). Using a pharmacologic inhibitor of MNK1/2, SEL201, we demonstrate that BRAFV600E-mutated cutaneous melanoma cells are reliant on MNK1/2 for invasion and lung metastasis.

A long noncoding RNA sensitizes genotoxic treatment by attenuating ATM activation and homologous recombination repair in cancers

Ataxia-telangiectasia mutated (ATM) is an apical kinase of the DNA damage response following DNA double-strand breaks (DSBs); however, the mechanisms of ATM activation are not completely understood. Long noncoding RNAs (lncRNAs) are a class of regulatory molecules whose significant roles in DNA damage response have started to emerge. However, how lncRNA regulates ATM activity remains unknown. Here, we identify an inhibitor of ATM activation, lncRNA HITT (HIF-1α inhibitor at translation level). Mechanistically, HITT directly interacts with ATM at the HEAT repeat domain, blocking MRE11-RAD50-NBS1 complex-dependent ATM recruitment, leading to restrained homologous recombination repair and enhanced chemosensitization. Following DSBs, HITT is elevated mainly by the activation of Early Growth Response 1 (EGR1), resulting in retarded and restricted ATM activation. A reverse association between HITT and ATM activity was also detected in human colon cancer tissues. Furthermore, HITTs sensitize DNA damaging agent-induced cell death both in vitro and in vivo. These findings connect lncRNA directly to ATM activity regulation and reveal potential roles for HITT in sensitizing cancers to genotoxic treatment.

Transcriptional regulation of adult neural stem/progenitor cells: tales from the subventricular zone

In rodents, well characterized neurogenic niches of the adult brain, such as the subventricular zone of the lateral ventricles and the subgranular zone of the hippocampus, support the maintenance of neural/stem progenitor cells (NSPCs) and the production of new neurons throughout the lifespan. The adult neurogenic process is dependent on the intrinsic gene expression signatures of NSPCs that make them competent for self-renewal and neuronal differentiation. At the same time, it is receptive to regulation by various extracellular signals that allow the modulation of neuronal production and integration into brain circuitries by various physiological stimuli. A drawback of this plasticity is the sensitivity of adult neurogenesis to alterations of the niche environment that can occur due to aging, injury or disease. At the core of the molecular mechanisms regulating neurogenesis, several transcription factors have been identified that maintain NSPC identity and mediate NSPC response to extrinsic cues. Here, we focus on REST, Egr1 and Dbx2 and their roles in adult neurogenesis, especially in the subventricular zone. We review recent work from our and other laboratories implicating these transcription factors in the control of NSPC proliferation and differentiation and in the response of NSPCs to extrinsic influences from the niche. We also discuss how their altered regulation may affect the neurogenic process in the aged and in the diseased brain. Finally, we highlight key open questions that need to be addressed to foster our understanding of the transcriptional mechanisms controlling adult neurogenesis.

ΗΙF1α, EGR1 and SP1 co-regulate the erythropoietin receptor expression under hypoxia: an essential role in the growth of non-small cell lung cancer cells

BACKGROUND

Overexpression of erythropoietin (EPO) and EPO receptor (EPO-R) is associated with poor prognosis in non-small-cell lung carcinoma (NSCLC). Hypoxia, a potent EPO inducer, is a major stimulating factor in the growth of solid tumors. However, how EPO-R expression is regulated under hypoxia is largely unknown.

METHODS

The role of EPO-R in NSCLC cell proliferation was assessed by RNA interference in vitro. Luciferase reporter assays were performed to map the promoter elements involved in the EPO-R mRNA transcription. Nuclear co-immunoprecipitation and chromatin immunoprecipitation were performed to assess the interaction among transcription factors HIF1α, SP1, and EGR1 in the regulation of EPO-R under hypoxia. The expression of key EPO-R transcription factors in clinical specimens were determined by immunohistochemistry.

RESULTS

Hypoxia induced a dosage and time dependent EPO-R mRNA expression in NSCLC cells. Knockdown of EPO-R reduced NSCLC cell growth under hypoxia (P < 0.05). Mechanistically, a SP1-EGR1 overlapped DNA binding sequence was essential to the hypoxia induced EPO-R transcription. In the early phase of hypoxia, HIF1α interacted with EGR1 that negatively regulated EPO-R. With the exit of EGR1 in late phase, HIF1α positively regulated EPO-R expression through additive interaction with SP1. In clinical NSCLC specimen, SP1 was positively while EGR1 was negatively associated with active EPO-R expression (P < 0.05).

CONCLUSIONS

HIF1α, SP1 and EGR1 mediated EPO-R expression played an essential role in hypoxia-induced NSCLC cell proliferation. Our study presents a novel mechanism of EPO-R regulation in the tumor cells, which may provide information support for NSCLC diagnosis and treatment.

The Role of MicroRNAs upon Epithelial-to-Mesenchymal Transition in Inflammatory Bowel Disease

Increasing evidence suggest the significance of inflammation in the progression of cancer, for example the development of colorectal cancer in Inflammatory Bowel Disease (IBD) patients. Long-lasting inflammation in the gastrointestinal tract causes serious systemic complications and breaks the homeostasis of the intestine, where the altered expression of regulatory genes and miRNAs trigger malignant transformations. Several steps lead from acute inflammation to malignancies: epithelial-to-mesenchymal transition (EMT) and inhibitory microRNAs (miRNAs) are known factors during multistage carcinogenesis and IBD pathogenesis. In this review, we outline the interactions between EMT components and miRNAs that may affect cancer development during IBD.

Stable Regulation of Senescence-Related Genes in Galactose-alpha1,3-galactose Epitope Knockout and Human Membrane Cofactor Protein hCD46 Pig

BACKGROUND

Pigs are considered suitable animal donor models for xenotransplantation. For successful organ transplantation, immune rejection must be overcome. Xenotransplantation has recently been successfully performed using galactose-alpha1,3-galactose epitopes knockout (GalTKO) and a human membrane cofactor protein (hCD46) in a pig model. However, the growth and lifespan of the grafted organ have not been evaluated. Therefore, in the present study we evaluated aging and 84 senescence-related genes using the RT² Profiler PCR array and whole blood samples from GalTKO/hCD46 Massachusetts General Hospital (MGH) pigs.

METHODS

Experimental groups were double GalTKO/hCD46 (5-month-old), single GalTKO/hCD46 (2-year-old), and non-genetically modified (>3.5-year-old; control group within the same strain). Age-matched white hairless Yucatan (WHY) miniature pig groups were used as controls.

RESULTS

Among the 19 senescence-related genes selected from the 84 genes for further evaluation, 13 were upregulated in the double GalTKO/hCD46 MGH pigs compared to control MGH pigs; however, in WHY pigs, only 4 genes were up- or down-regulated among the 19 genes. Moreover, in double GalTKO/hCD46 MGH and WHY pigs, the expression of the 19 genes changed only 1- to 2-fold, suggesting that there were no significant differences in senescence signals between the 2 pig lines.

CONCLUSIONS

The present results indicate that the double GalTKO/hCD46 MGH pig might be a suitable model for human xenotransplantation studies. However, we used a limited number of experimental individuals, so further studies using larger experimental groups should be conducted to verify the present results.

The Mechanisms Underlying PTEN Loss in Human Tumors Suggest Potential Therapeutic Opportunities

In this review, we will first briefly describe the diverse molecular mechanisms associated with PTEN loss of function in cancer. We will then proceed to discuss the molecular mechanisms linking PTEN loss to PI3K activation and demonstrate how these mechanisms suggest possible therapeutic approaches for patients with PTEN-null tumors.

Propranolol exhibits activity against hemangiomas independent of beta blockade

Propranolol is a widely used beta blocker that consists of a racemic mixture of R and S stereoisomers. Only the S stereoisomer has significant activity against the beta-adrenergic receptor. A fortuitous clinical observation was made in an infant who received propranolol for cardiac disease, and regression of a hemangioma of infancy was noted. This has led to the widespread use of propranolol for the treatment of large and life-threatening hemangiomas of infancy. Infants receiving propranolol require monitoring to ensure that they do not suffer from side effects related to beta blockade. The exact mechanism of activity of propranolol in hemangioma of infancy is unknown. In this study, we treated hemangioma stem cells with both beta blockade active S- and inactive R-propranolol and looked for genes that were coordinately regulated by this treatment. Among the genes commonly downregulated, Angiopoietin-like 4 (ANGPTL4) was among the most regulated. We confirmed that propranolol isomers downregulated ANGPTL4 in endothelial cells, with greater downregulation of ANGPTL4 using the beta blockade inactive R-propranolol. ANGPTL4 is present in human hemangiomas of infancy. Finally, R-propranolol inhibited the growth of bEnd.3 hemangioma cells in vivo. The implication of this is that hemangioma growth can be blocked without the side effects of beta blockade. Given that humans have been exposed to racemic propranolol for decades and thus to R-propranolol, clinical development of R-propranolol for hemangiomas of infancy and other angiogenic diseases is warranted.

Pathogenetic implications of early growth response 1 in Ewing sarcoma

Ewing sarcoma (ES) is the second most common primary malignant bone tumour, mainly occurs in children and adolescents, and has an overwhelming mortality. Despite extensive studies, few effective oncogenic signals have been described. Therefore, it is crucial to exploit novel pathognomonic factors and targetable biomarkers for ES patients. Based on previous studies, we speculate that insulin-like growth factor 1 receptor (IGF1R), which is upregulated by early growth response 1 (EGR1), may play a pivotal role in strengthening the downward transmission of IGF1 cascades. Therefore, in this study, we concentrated on determining the pathogenetic contribution of EGR1 in diverse ES cells. This report is the first to study the pathogenic role of EGR1 in ES. ES cells were cultured and transfected with Stealth RNAi human EGR1 small interfering RNA (siRNA) or negative control. Cell proliferation and invasion potential were measured. mRNA and protein expression of EGR1, IGF1R, and EWS-FLI1 also were assessed. In all EGR1 siRNA-transfected cells (SK-ES-1, RD-ES, and HS863.T), cell proliferation and invasive potential decreased significantly in EGR1 siRNA-transfected ES cells. mRNA and protein expression for EGR1, IGF1R, and EWS-FLI1 were also significantly reduced. In conclusion, EGR1 upregulated IGF1R expression and enhanced the expression of the oncogenic fusion protein EWS-FLI1. The EWS-FLI1/EGR1/IGF1R cascade combined with the previously confirmed pathways can form a speculative circuit, implicating positive feedback for tumourigenesis in ES. Therefore, EGR1 inhibitors are expected to be useful for the treatment of ES by preventing oncogenic IGF1/IGF1R expression.

Trans-acting non-synonymous variant of FOXA1 predisposes to hepatocellular carcinoma through modulating FOXA1-ERα transcriptional program and may have undergone natural selection

Interplay of pioneer transcription factor forkhead box A1 (FOXA1) and estrogen receptor has been implicated in sexual dimorphism in hepatocellular carcinoma (HCC), but etiological relevance of its polymorphism was unknown. In the case control study (1152 patients versus1242 controls), we observed significant increase in HCC susceptibility in hepatitis B virus carriers associated with a non-synonymous Thr83Ala variant of FOXA1 (odds ratio [OR], 1.28; 95% confidence interval [CI], 1.11−1.48, for Ala83-containing genotype, after validation in an independent population with 933 patients versus 1030 controls), a tightly linked (CGC)5/6or7 repeat polymorphism at its promoter (OR 1.32; 95% CI 1.10–1.60, for (CGC)6or7-repeat-containing genotype), and their combined haplotype (OR 1.50; 95% CI 1.24–1.81, for (CGC)6or7−Ala83 haplotype). The susceptible FOXA1-Ala83 impairs its interaction with ERα, attenuates transactivation toward some of their dual target genes, such as type 1 iodothyronine deiodinase, UDP glucuronosyltransferase 2 family, polypeptide B17 and sodium/taurocholate cotransporting polypeptide, but correlates with strengthened cellular expression of α-fetoprotein (AFP) and elevated AFP serum concentration in HCC patients (n = 1096). The susceptible FOXA1 cis-variant with (CGC)6or7 repeat strengthens the binding to transcription factor early growth response 1 and enhances promoter activity and gene expression. Evolutionary population genetics analyses with public datasets reveal significant population differentiation and unique haplotype structure of the derived protective FOXA1-Thr83 and suggest that it may have undergone positive natural selection in Chinese population. These findings epidemiologically highlight the functional significance of FOXA1-ERα transcriptional program and regulatory network in liver cancer development.

MicroRNA-34a suppresses the invasion and migration of colorectal cancer cells by enhancing EGR1 and inhibiting vimentin

MicroRNAs (miRNAs/miRs) are small non-coding RNAs that serve a post-transcriptional regulatory role in eukaryotes. Previous studies have demonstrated that the expression of miR-34a in colorectal cancer (CRC) tissues is decreased compared with that in normal colorectal tissues. However, the role of miR-34a in the invasion and metastasis of CRC remains unclear. In the present study, the levels of miR-34a expression were measured in various CRC cell lines. The cells were transfected with miR-34a mimics or inhibitors in order to assess the proliferation rate, and the colony forming, invasive and migratory abilities. Furthermore, the protein expression levels of vimentin and early growth response protein 1 (EGR1) were examined by western blot analysis. The results revealed that the expression of miR-34a was low in SW620, RKO, LoVo and Caco-2 cell lines and high in the SW480 and SW1116 cell lines. The migration, invasion and proliferation levels of SW480 cells were facilitated by decreasing the expression of miR-34a. Transient transfection with miR-34a mimics in SW620 cells caused a notable decrease in cell migration, invasion and proliferation levels compared with the control group, and a downregulation of vimentin and upregulation of EGR1 protein expression. The present study demonstrated that miR-34a was deregulated in a highly invasive CRC cell lines, and that it may attenuate the migratory, invasive and proliferative capabilities of CRC cells by enhancing the expression of EGR1 and inhibiting that of vimentin. The results of the present study represent important progress towards understanding the mechanisms of CRC recurrence and metastasis.

EGR1 regulates angiogenic and osteoclastogenic factors in prostate cancer and promotes metastasis

Early growth response-1 (EGR1) is a transcription factor correlated with prostate cancer (PC) progression in a variety of contexts. For example, EGR1 levels increase in response to suppressed androgen receptor signaling or loss of the tumor suppressor, PTEN. EGR1 has been shown to regulate genes influencing proliferation, apoptosis, immune cell activation, and matrix degradation, among others. Despite this, the impact of EGR1 on PC metastatic colonization is unclear. We demonstrate using a PC model (DU145/RasB1) of bone and brain metastasis that EGR1 expression regulates angiogenic and osteoclastogenic properties of metastases. We have shown previously that FN14 (TNFRSF12A) and downstream NF-κB signaling is required for metastasis in this model. Here we demonstrate that FN14 ligation also leads to NF-κB-independent, MEK-dependent EGR1 expression. EGR1-depletion in DU145/RasB1 cells reduced both the number and size of metastases but did not affect primary tumor growth. Decreased EGR1 expression led to reduced blood vessel density in brain and bone metastases as well as decreased osteolytic bone lesion area and reduced numbers of osteoclasts at the bone-tumor interface. TWEAK (TNFSF12) induced several EGR1-dependent angiogenic and osteoclastogenic factors (e.g. PDGFA, TGFB1, SPP1, IL6, IL8, and TGFA, among others). Consistent with this, in clinical samples of PC, the level of several genes encoding angiogenic/osteoclastogenic pathway effectors correlated with EGR1 levels. Thus, we show here that EGR1 has a direct effect on prostate cancer metastases. EGR1 regulates angiogenic and osteoclastogenic factors, informing the underlying signaling networks that impact autonomous and microenvironmental mechanisms of cancer metastases.

Under inflammatory stimuli mesenteric mesothelial cells transdifferentiate into macrophages and produce pro-inflammatory cytokine IL-6

OBJECTIVE

Inflammatory stimuli inducing epithelial-to-mesenchymal transition (EMT) can transdifferentiate mesenteric mesothelial cells into macrophages.

METHODS

Sprague Dawley rat mesenteric mesothelial cells were used as a model. 1 ml Freund adjuvant was injected into the peritoneal cavity of rat and GM-CSF treatment was used to induce inflammation. IL-10 and IL-6 expression were studied by immunocytochemistry and Western blot analysis both in vivo and in vitro.

RESULTS

Control mesothelial cell express anti-inflammatory IL-10, but no pro-inflammatory IL-6 expression could be detected in them. By the time of inflammation, IL-6 expression increased (reached the maximum level at the fifth day of inflammation), parallel to this the IL-10 entirely disappeared from these cells. In vitro GM-CSF treatment resulted in similar changes. As the mesothelial cells started to recover (at the eighth day of inflammation) IL-6 expression decreased and IL-10 level started to increase again.

CONCLUSION

These data show that under inflammatory stimuli mesothelial cells-like macrophages-can produce pro-inflammatory cytokines.

Meta-Analysis of Microarray Expression Studies on Metformin in Cancer Cell Lines

Several studies have demonstrated that metformin (MTF) acts with variable efficiency as an anticancer agent. The pleiotropic anticancer effects of MTF on cancer cells have not been fully explored yet. By interrogating the Gene Expression Omnibus (GEO) for microarray expression data, we identified eight eligible submissions, representing five different studies, that employed various conditions including different cell lines, MTF concentrations, treatment durations, and cellular components. A compilation of the data sets of 13 different conditions contained 443 repeatedly up- and 387 repeatedly down-regulated genes; the majority of these 830 differentially expressed genes (DEGs) were associated with higher MTF concentrations and longer MTF treatment. The most frequently upregulated genes include DNA damage inducible transcript 4 (DDIT4), chromodomain helicase DNA binding protein 2 (CHD2), endoplasmic reticulum to nucleus signaling 1 (ERN1), and growth differentiation factor 15 (GDF15). The most commonly downregulated genes include arrestin domain containing 4 (ARRDC4), and thioredoxin interacting protein (TXNIP). The most significantly (p-value < 0.05, Fisher’s exact test) overrepresented protein class was entitled, nucleic acid binding. Cholesterol biosynthesis and other metabolic pathways were specifically affected by downregulated pathway molecules. In addition, cell cycle pathways were significantly related to the data set. Generated networks were significantly related to, e.g., carbohydrate and lipid metabolism, cancer, cell cycle, and DNA replication, recombination, and repair. A second compilation comprised genes that were at least under one condition up- and in at least another condition down-regulated. Herein, the most frequently deregulated genes include nuclear paraspeckle assembly transcript 1 (NEAT1) and insulin induced gene 1 (INSIG1). The most significantly overrepresented protein classes in this compilation were entitled, nucleic acid binding, ubiquitin-protein ligase, and mRNA processing factor. In conclusion, this study provides a comprehensive list of deregulated genes and biofunctions related to in vitro MTF application and individual responses to different conditions. Biofunctions affected by MTF include, e.g., cholesterol synthesis and other metabolic pathways, cell cycle, and DNA replication, recombination, and repair. These findings can assist in defining the conditions in which MTF exerts additive or synergistic effects in cancer treatment.

DNA Methylation Readers and Cancer: Mechanistic and Therapeutic Applications

DNA methylation is a major epigenetic process that regulates chromatin structure which causes transcriptional activation or repression of genes in a context-dependent manner. In general, DNA methylation takes place when methyl groups are added to the appropriate bases on the genome by the action of "writer" molecules known as DNA methyltransferases. How these methylation marks are read and interpreted into different functionalities represents one of the main mechanisms through which the genes are switched "ON" or "OFF" and typically involves different types of "reader" proteins that can recognize and bind to the methylated regions. A tightly balanced regulation exists between the "writers" and "readers" in order to mediate normal cellular functions. However, alterations in normal methylation pattern is a typical hallmark of cancer which alters the way methylation marks are written, read and interpreted in different disease states. This unique characteristic of DNA methylation "readers" has identified them as attractive therapeutic targets. In this review, we describe the current state of knowledge on the different classes of DNA methylation "readers" identified thus far along with their normal biological functions, describe how they are dysregulated in cancer, and discuss the various anti-cancer therapies that are currently being developed and evaluated for targeting these proteins.

Ferulic acid improves self-renewal and differentiation of human tendon-derived stem cells by upregulating early growth response 1 through hypoxia

We aimed to investigate the potential beneficial effect of ferulic acid (FA) on stemness of human tendon-derived stem cells (hTSCs) in vitro and to elucidate the underlying molecular mechanism. The self-renewal ability of hTSCs was evaluated by colony formation and cell proliferation was determined by CCK-8 kit. Adipogenesis, osteogenesis, and chondrogenesis were determined by Oil Red O, Alizarin Red, and Alcian Blue stainings, respectively. Relative mRNA levels of PPARγ, Col2A1, Acan, Runx2, HIF1α, and EGR1 were measured with real-time PCR. Protein levels of HIF1α and EGR1 were detected by western blot. Direct binding of HIF1α with EGR1 promoter was analyzed by ChIP assay. Hypoxia-induced expression of EGR1 was interrogated by luciferase reporter assay. We demonstrated that FA treatment improved both self-renewal ability and multi-differentiation potential of hTSCs. FA induced hypoxia which in turn upregulated EGR1 expression via direct association with its hypoxia response element consensus sequence. Furthermore, we showed that both HIF1α and EGR1 were required for the enhancing effects of FA on hTSC self-renewal and differentiation. We hereby characterize the beneficial effect of FA on the stemness of hTSCs and highlight the critical role of HIF1α-EGR1 axis in this process.

Inhibition of DUSP6 sensitizes ovarian cancer cells to chemotherapeutic agents via regulation of ERK signaling response genes

Dual specificity phosphatase 6 (DUSP6) is a protein phosphatase that deactivates extracellular-signal-regulated kinase (ERK). Since the ovarian cancer biomarker human epididymis protein 4 (HE4) interacts with the ERK pathway, we sought to determine the relationship between DUSP6 and HE4 and elucidate DUSP6's role in epithelial ovarian cancer (EOC). Viability assays revealed a significant decrease in cell viability with pharmacological inhibition of DUSP6 using (E/Z)-BCI hydrochloride in ovarian cancer cells treated with carboplatin or paclitaxel, compared to treatment with either agent alone. Quantitative PCR was used to evaluate levels of ERK pathway response genes to BCI in combination with recombinant HE4 (rHE4), carboplatin, and paclitaxel. Expression of EGR1, a promoter of apoptosis, was higher in cells co-treated with BCI and paclitaxel or carboplatin than in cells treated with chemotherapeutic agents alone, while expression of the proto-oncogene c-JUN was decreased with co-treatment. The effect of BCI on the expression of these two genes opposed that of rHE4. Pathway focused quantitative PCR also revealed suppression of ERBB3 in cells co-treated with BCI plus carboplatin or paclitaxel. Finally, expression levels of DUSP6 in EOC tissue were evaluated by immunohistochemistry, revealing significantly increased levels of DUSP6 in serous EOC tissue compared to adjacent normal tissue. A positive correlation between HE4 and DUSP6 levels was determined by Spearman Rank correlation. In conclusion, DUSP6 inhibition sensitizes ovarian cancer cells to chemotherapeutic agents and alters gene expression of ERK response genes, suggesting that DUSP6 could plausibly function as a novel therapeutic target to reduce chemoresistance in EOC.

Identification, Characterization, and Regulatory Mechanisms of a Novel EGR1 Splicing Isoform

EGR1 is a transcription factor expressed in many cell types that regulates genes involved in different biological processes including growth, proliferation, and apoptosis. Dysregulation of EGR1 expression has been associated with many pathological conditions such as tumors and brain diseases. Known molecular mechanisms underlying the control of EGR1 function include regulation of transcription, mRNA and protein stability, and post-translational modifications. Here we describe the identification of a splicing isoform for the human EGR1 gene. The newly identified splicing transcript encodes a shorter protein compared to the canonical EGR1. This isoform lacks a region belonging to the N-terminal activation domain and although it is capable of entering the nucleus, it is unable to activate transcription fully relative to the canonical isoform.

Genomic variants within the long non-coding RNA H19 confer risk of breast cancer in Iranian population

OBJECTIVE

The long non-coding RNA (lncRNA) H19 is an imprinted lncRNA with acknowledged roles in carcinogenesis.

METHODS

In the current study, we genotyped two single nucleotide polymorphisms (SNPs) within H19 in 111 breast cancer patients and 130 age-matched healthy subjects using tetra primer-ARMS-PCR technique. The T allele of rs2839698 conferred breast cancer risk in the assessed population (OR (95% CI) = 2.52 (1.75-3.64), adjusted P value = 1.3E-6), while and the T allele of rs217727 had a protective effect (OR (95% CI) = 0.42 (0.27-0.66), adjusted P value = 2.8E-4). Both SNPs were associated with breast cancer risk in recessive, dominant and co-dominant models. The T C haplotype (rs2839698 and rs217727) significantly increased risk of breast cancer (OR (95% CI) = 2.4 (1.65-3.45), adjusted P value = 1.2E-5), while the C T haplotype had a protective role (OR (95% CI) = 0.31 (0.18-0.52), adjusted P value = 2.03E-5). The present study highlights the role of H19 SNPs in conferring risk of breast cancer in Iranian population. Future studies with larger sample sizes are required to verify these data.

Egr1 mediates retinal vascular dysfunction in diabetes mellitus via promoting p53 transcription

Objectives

This study focused on investigating the expression and underlying molecular mechanism of early growth response 1 (Egr1) in diabetic retinopathy.

Methods

A microarray assay was applied to examine differentially expressed genes in the retina tissues of normal rats, as well as in those of streptozotocin‐induced diabetic rats. Human retinal vascular endothelial cells (HRVECs) transfected with sh‐NC, sh‐Egr1 or sh‐Egr1+ pVax1‐p53 were cultured under high‐glucose conditions and then used to explore the role of Egr1 in vitro. The effect of Egr1 on retinal vascular dysfunction caused by diabetes was examined by sh‐Egr1 administration in vivo

Results

Early growth response 1 was found to be up‐regulated in the retinas of diabetic rats compared to those of normal rats. Down‐regulation of Egr1 in HRVECs under high‐glucose conditions inhibited the apoptosis, migration and tube formation in vitro. Moreover, sh‐Egr1 partially reduced the injurious effects of hyperglycaemia on retinal vascular function by decreasing apoptotic cells and microvascular formation in vivo. The reduction of Egr1 evidently down‐regulated the p53 expression. Overexpression of p53 rescued the inhibition of sh‐Egr1 in HRVECs under high‐glucose concentration on apoptosis, migration and tube formation in vitro.

Conclusion

Down‐regulation of Egr1 partially reduced the injurious effects of hyperglycaemia on retinal vascular function via inhibiting p53 expression.

Prostate cancer promotes a vicious cycle of bone metastasis progression through inducing osteocytes to secrete GDF15 that stimulates prostate cancer growth and invasion

Bone is the most frequent site of prostate cancer (PCa) metastasis; however, little is known about the role of the most common cell in bone, the osteocyte (OCy), in cancer biology. In this study we explored the crosstalk between PCa cells and OCys to determine if it contributes to PCa progression. PCa cells induced OCys to promote PCa proliferation, migration and invasion. A chemokine screen revealed that PCa cell induced OCys to produce growth-derived factor 15 (GDF15). Knockdown of GDF15 in OCys demonstrated that PCa cells conferred the ability on OCys to promote PCa proliferation, migration and invasion through GDF15. Consistent with this finding was the observation that the GDF15 receptor, GFRAL, was expressed on multiple PCa cell lines. Transcription factor array screening of PCa cells exposed to OCys with or without knockdown of GDF15 revealed that GDF15 in OCys promoted early growth response 1 (EGR1) expression in the PCa cells. Knockdown of EGR1 expression in PCa cells revealed it was required for the OCy-derived GDF15-mediated induction of in vitro PCa cell proliferation, migration and invasion. Subcutaneous co-injection of PCa cells and OCys into mice revealed that OCys promoted tumor growth in vivo, which was diminished by knockdown of GDF15 in the OCys. Knockdown of GDF15 in the tibiae diminished growth of PCa cancer cells injected into the tibiae, which was accompanied by decreased tumor cell proliferation and EGR1 expression. These results shed light on a novel mechanism through which PCa cells educate OCys to promote progression of PCa bone metastasis. They also suggest that targeting of GDF15-based and EGR1-based signaling pathways should be further explored for their potential to diminish progression of PCa bone metastasis.

Complex karyotype in myelodysplastic syndromes: Diagnostic procedure and prognostic susceptibility

Complex karyotype (CK) is a poor prognosis factor in hematological malignancies. Studies have shown that the presence of CK in myelodysplastic syndrome (MDS) can be associated with MDS progression to acute myeloid leukemia. The goal of this review was to examine the relationship between different types of CK with MDS, as well as its possible role in the deterioration and progression of MDS to leukemia. The content used in this paper has been obtained by a PubMed and Google Scholar search of English language papers (1975-2018) using the terms complex karyotype and myelodysplastic syndromes. A single independent abnormality can be associated with a good prognosis. However, the coexistence of a series of abnormalities can lead to CK, which is associated with the deterioration of MDS and its progression to leukemia. Therefore, CK may be referred to as a prognostic factor in MDS. The detection of independent cytogenetic disorders that altogether can result in CK could be used as a prognostic model for laboratory and clinical use.

c-MYB and DMTF1 in Cancer

The c-Myb gene encodes a transcription factor that regulates cell proliferation, differentiation, and apoptosis through protein-protein interaction and transcriptional regulation of signaling pathways. The protein is frequently overexpressed in human leukemias, breast cancers, and other solid tumors suggesting that it is a bona fide oncogene. c-MYB is often overexpressed by translocation in human tumors with t(6;7)(q23;q34) resulting in c-MYB-TCRβ in T cell ALL, t(X;6)(p11;q23) with c-MYB-GATA1 in acute basophilic leukemia, and t(6;9)(q22-23;p23-24) with c-MYB-NF1B in adenoid cystic carcinoma. Antisense oligonucleotides to c-MYB were developed to purge bone marrow cells to eliminate tumor cells in leukemias. Recently, small molecules that inhibit c-MYB activity have been developed to disrupt its interaction with p300. The Dmp1 (cyclin D binding myb-like protein 1; Dmtf1) gene was isolated through its virtue for binding to cyclin D2. It is a transcription factor that has a Myb-like repeat for DNA binding. The Dmtf1 protein directly binds to the Arf promoter for transactivation and physically interacts with p53 to activate the p53 pathway. The gene is hemizygously deleted in 35-42% of human cancers and is associated with longer survival. The significances of aberrant expression of c-MYB and DMTF1 proteins in human cancers and their clinical significances are discussed.

Inflammation-Induced Epithelial-to-Mesenchymal Transition and GM-CSF Treatment Stimulate Mesenteric Mesothelial Cells to Transdifferentiate into Macrophages

In our previous work, we showed that during inflammation-induced epithelial-to-mesenchymal transition (EMT), mesenteric mesothelial cells express ED1 (pan-macrophage marker), indicating that they are transformed into macrophage-like cells. In this paper, we provide additional evidences about this transition by following the phagocytic activity and the TNFα production of mesenteric mesothelial cells during inflammation. Upon injection of India ink particles or fluorescent-labeled bioparticles (pHrodo) into the peritoneal cavity of rats pretreated with Freund's adjuvant, we found that mesothelial cells efficiently engulfed these particles. A similar increase of internalization could be observed by mesothelial cells in GM-CSF pretreated primary mesenteric culture. Since macrophages are the major producers of tumor necrosis factor, TNFα, we investigated expression level of TNFα during inflammation-induced EMT and found that TNFα was indeed expressed in these cells, reaching the highest level at the 5th day of inflammation. Since TNFα is one of the target genes of early growth response (EGR1) transcription factor, playing important role in monocyte-macrophage differentiation, expression of EGR1 in mesothelial cells was also investigated by Western blot and immunocytochemistry. While mesothelial cells did not express EGR1, a marked increase was observed in mesothelial cells by the time of inflammation. Parallel to this, nuclear translocation of EGR1 was shown by immunocytochemistry at the day 5 of inflammation. Caveolin-1 level was high and ERK1/2 became phosphorylated as the inflammation proceeded showing a slight decrease when the regeneration started. Our present data support the idea that under special stimuli, mesenteric mesothelial cells are able to transdifferentiate into macrophages, and this transition is regulated by the caveolin-1/ERK1/2/EGR1 signaling pathway.

MicroRNA-181a-5p suppresses cell proliferation by targeting Egr1 and inhibiting Egr1/TGF-β/Smad pathway in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the leading cause of cancer mortality worldwide. Early growth response factor 1 (Egr1) plays a crucial role in cancer progression. However, its precise role in HCC has not been clear. Here, we identified the aggravating role of Egr1 in cell proliferation of HCC firstly. The expression of Egr1 was significantly increased in HCC tissues. Functionally, overexpression of Egr1 enhanced, whereas silenced Egr1 expression attenuated HCC cells proliferation in vitro. Mechanistically, up-regulated Egr1 induced cell proliferation through activating Transforming growth factor (TGF)-β1/Smad signaling pathway concomitantly with upregulation of p-Smad2 and p-Smad3. Secondly, miR-181a-5p was down-regulated in clinical HCC specimens and its expression was inversely correlated with Egr1 expression. Functionally, overexpression of miR-181a-5p inhibited, whereas decreased expression of miR-181a-5p promoted HCC cells proliferation in vitro. Furthermore, we demonstrated that miR-181a-5p overexpression directly suppressed Egr1, resulting in a down-regulated TGF-β1/Smad pathway. Besides, the silenced Egr1 expression could rescue the enhanced cell proliferation induced by miR-181a-5p inhibitor. Thus, we concluded that miR-181a-5p is a negative regulator of Egr1 that can suppress tumor proliferation in HCC through targeting Egr1/TGF-β1/Smad pathway, which may be a potential therapeutic approach of HCC.