Human differentiation-related gene NDRG1 is a Myc downstream-regulated gene that is repressed by Myc on the core promoter region

Antitumor Activity of Piceamycin by Upregulation of N-Myc Downstream-Regulated Gene 1 in Human Colorectal Cancer Cells

Piceamycin (1), a macrocyclic lactam isolated from the silkworm's gut (Streptomyces sp. SD53 strain), reportedly possesses antibacterial activity. However, the potential anticancer activity and molecular processes underlying 1 have yet to be reported. Colorectal cancer (CRC) is high-risk cancer and accounts for 10% of all cancer cases worldwide. The high prevalence of resistance to radiation or chemotherapy means that patients with advanced CRC have a poor prognosis, with high recurrence and metastasis potential. Therefore, the present study investigated the antitumor effect and underlying mechanisms of 1 in CRC cells. The growth-inhibiting effect of 1 in CRC cells was correlated with the upregulation of a tumor suppressor, N-myc downstream-regulated gene 1 (NDRG1). Additionally, 1 induced G₀/G₁ cell cycle arrest and apoptosis and inhibited the migration of CRC cells. Notably, 1 disrupted the interaction between NDRG1 and c-Myc in CRC cells. In a mouse model with HCT116-implanted xenografts, the antitumor activity of 1 was confirmed by NDRG1 modulation. Overall, these findings show that 1 is a potential candidate for CRC treatment through regulation of NDGR1-mediated functionality.

The Ni(II)-Binding Activity of the Intrinsically Disordered Region of Human NDRG1, a Protein Involved in Cancer Development

Nickel exposure is associated with tumors of the respiratory tract such as lung and nasal cancers, acting through still-uncharacterized mechanisms. Understanding the molecular basis of nickel-induced carcinogenesis requires unraveling the mode and the effects of Ni(II) binding to its intracellular targets. A possible Ni(II)-binding protein and a potential focus for cancer treatment is hNDRG1, a protein induced by Ni(II) through the hypoxia response pathway, whose expression correlates with higher cancer aggressiveness and resistance to chemotherapy in lung tissue. The protein sequence contains a unique C-terminal sequence of 83 residues (hNDRG1*C), featuring a three-times-repeated decapeptide, involved in metal binding, lipid interaction and post-translational phosphorylation. In the present work, the biochemical and biophysical characterization of unmodified hNDRG1*C was performed. Bioinformatic analysis assigned it to the family of the intrinsically disordered regions and the absence of secondary and tertiary structure was experimentally proven by circular dichroism and NMR. Isothermal titration calorimetry revealed the occurrence of a Ni(II)-binding event with micromolar affinity. Detailed information on the Ni(II)-binding site and on the residues involved was obtained in an extensive NMR study, revealing an octahedral paramagnetic metal coordination that does not cause any major change of the protein backbone, which is coherent with CD analysis. hNDRG1*C was found in a monomeric form by light-scattering experiments, while the full-length hNDRG1 monomer was found in equilibrium between the dimer and tetramer, both in solution and in human cell lines. The results are the first essential step for understanding the cellular function of hNDRG1*C at the molecular level, with potential future applications to clarify its role and the role of Ni(II) in cancer development.

TF-DUBTACs Stabilize Tumor Suppressor Transcription Factors

Targeted protein degradation approaches have been widely used for degrading oncogenic proteins, providing a potentially promising therapeutic strategy for cancer treatment. However, approaches to targeting tumor suppressor proteins are very limited, and only a few agonists have been developed to date. Here, we report the development of a platform termed TF-DUBTAC, which links a DNA oligonucleotide to a covalent ligand of the deubiquitinase OTUB1 via a click reaction, to selectively stabilize tumor suppressor transcription factors. We developed three series of TF-DUBTACs, namely, FOXO-DUBTAC, p53-DUBTAC, and IRF-DUBTAC, which stabilize FOXO3A, p53, and IRF3 in cells, respectively, in an OTUB1-dependent manner. These results suggest that TF-DUBTAC is a generalizable platform to achieve selective stabilization of tumor suppressor transcription factors as a therapeutic means to suppress tumorigenesis.

Iron-Chelation Treatment by Novel Thiosemicarbazone Targets Major Signaling Pathways in Neuroblastoma

Despite constant advances in the field of pediatric oncology, the survival rate of high-risk neuroblastoma patients remains poor. The molecular and genetic features of neuroblastoma, such as MYCN amplification and stemness status, have established themselves not only as potent prognostic and predictive factors but also as intriguing targets for personalized therapy. Novel thiosemicarbazones target both total level and activity of a number of proteins involved in some of the most important signaling pathways in neuroblastoma. In this study, we found that di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone (DpC) potently decreases N-MYC in MYCN-amplified and c-MYC in MYCN-nonamplified neuroblastoma cell lines. Furthermore, DpC succeeded in downregulating total EGFR and phosphorylation of its most prominent tyrosine residues through the involvement of NDRG1, a positive prognostic marker in neuroblastoma, which was markedly upregulated after thiosemicarbazone treatment. These findings could provide useful knowledge for the treatment of MYC-driven neuroblastomas that are unresponsive to conventional therapies.

Progesterone receptor isoform ratio dictates antiprogestin/progestin effects on breast cancer growth and metastases: A role for NDRG1

Progesterone receptors (PR) ligands are being tested in luminal breast cancer. There are mainly two PR isoforms, PRA and PRB, and their ratio (PRA/PRB) may be predictive of antiprogestin response. Our aim was to investigate: the impact of the PR isoform ratio on metastatic behavior, the PR isoform ratio in paired primary tumors and lymph node metastases (LNM) and, the effect of antiprogestin/progestins on metastatic growth. Using murine and human metastatic models, we demonstrated that tumors with PRB > PRA (PRB-H) have a higher proliferation index but less metastatic ability than those with PRA > PRB (PRA-H). Antiprogestins and progestins inhibited metastatic burden in PRA-H and PRB-H models, respectively. In breast cancer samples, LNM retained the same PRA/PRB ratio as their matched primary tumors. Moreover, PRA-H LNM expressed higher total PR levels than the primary tumors. The expression of NDRG1, a metastasis suppressor protein, was higher in PRB-H compared with PRA-H tumors and was inversely regulated by antiprogestins/progestins. The binding of the corepressor SMRT at the progesterone responsive elements of the NDRG1 regulatory sequences, together with PRA, impeded its expression in PRA-H cells. Antiprogestins modulate the interplay between SMRT and AIB1 recruitment in PRA-H or PRB-H contexts regulating NDRG1 expression and thus, metastasis. In conclusion, we provide a mechanistic interpretation to explain the differential role of PR isoforms in metastatic growth and highlight the therapeutic benefit of using antiprogestins in PRA-H tumors. The therapeutic effect of progestins in PRB-H tumors is suggested. This article is protected by copyright. All rights reserved.

MYC Hyperactivates Wnt Signaling in APC/CTNNB1-Mutated Colorectal Cancer Cells through miR-92a-Dependent Repression of DKK3

Activation of Wnt signaling is among the earliest events in colon cancer development. It is achieved either via activating mutations in the CTNNB1 gene encoding β-catenin, the key transcription factor in the Wnt pathway, or most commonly by inactivating mutations affecting APC, a major β-catenin binding partner and negative regulator. However, our analysis of recent Pan Cancer Atlas data revealed that CTNNB1 mutations significantly co-occur with those affecting Wnt receptor complex components (e.g., Frizzled and LRP6), underscoring the importance of additional regulatory events even in the presence of common APC/CTNNB1 mutations. In our effort to identify non-mutational hyperactivating events, we determined that KRAS-transformed murine colonocytes overexpressing direct β-catenin target MYC show significant upregulation of the Wnt signaling pathway and reduced expression of Dickkopf 3 (DKK3), a reported ligand for Wnt co-receptors. We demonstrate that MYC suppresses DKK3 transcription through one of miR-17-92 cluster miRNAs, miR-92a. We further examined the role of DKK3 by overexpression and knockdown and discovered that DKK3 suppresses Wnt signaling in Apc-null murine colonic organoids and human colon cancer cells despite the presence of downstream activating mutations in the Wnt pathway. Conversely, MYC overexpression in the same cell lines resulted in hyperactive Wnt signaling, acquisition of epithelial-to-mesenchymal transition markers, and enhanced migration/invasion in vitro and metastasis in a syngeneic orthotopic mouse colon cancer model. IMPLICATIONS: Our results suggest that the MYC→miR-92a-|DKK3 axis hyperactivates Wnt signaling, forming a feed-forward oncogenic loop.

The Relationship of Glutathione-S-Transferase and Multi-Drug Resistance-Related Protein 1 in Nitric Oxide (NO) Transport and Storage

Nitric oxide is a diatomic gas that has traditionally been viewed, particularly in the context of chemical fields, as a toxic, pungent gas that is the product of ammonia oxidation. However, nitric oxide has been associated with many biological roles including cell signaling, macrophage cytotoxicity, and vasodilation. More recently, a model for nitric oxide trafficking has been proposed where nitric oxide is regulated in the form of dinitrosyl-dithiol-iron-complexes, which are much less toxic and have a significantly greater half-life than free nitric oxide. Our laboratory has previously examined this hypothesis in tumor cells and has demonstrated that dinitrosyl-dithiol-iron-complexes are transported and stored by multi-drug resistance-related protein 1 and glutathione-S-transferase P1. A crystal structure of a dinitrosyl-dithiol-iron complex with glutathione-S-transferase P1 has been solved that demonstrates that a tyrosine residue in glutathione-S-transferase P1 is responsible for binding dinitrosyl-dithiol-iron-complexes. Considering the roles of nitric oxide in vasodilation and many other processes, a physiological model of nitric oxide transport and storage would be valuable in understanding nitric oxide physiology and pathophysiology.

N-MYC Downstream Regulated Gene 4 (NDRG4), a Frequent Downregulated Gene through DNA Hypermethylation, plays a Tumor Suppressive Role in Esophageal Adenocarcinoma

Simple Summary

Esophageal adenocarcinoma has become a major clinical challenge in the western world due to its rapid increasing incidence and poor overall prognosis. Understanding the molecular events of its tumorigenesis is the key to better diagnosis and development of better therapeutic strategies. In the current study we aimed to identify epigenetic alteration targets in esophageal adenocarcinoma. We focused on a candidate gene, NDRG4 (N-myc downregulated gene 4). We found that NDRG4 was frequent downregulated in esophageal adenocarcinoma through DNA hypermethylation of its promoter region. Re-expression of NRDG4 in cancer cells significantly suppressed tumor growth via inhibition of cell proliferation. These results will improve our understanding on how dysfunction of NDRG4 contributes to esophageal adenocarcinoma. DNA hypermethylation of NDRG4 may be a useful biomarker in clinical monitoring of esophageal adenocarcinoma patients.

Abstract

The incidence of esophageal adenocarcinoma (EAC) has been rising dramatically in the past few decades in the United States and Western world. The N-myc downregulated gene 4 (NDRG4) belongs to the human NDRG family. In this study, we aimed to identify the expression levels, regulation, and functions of NDRG4 in EAC. Using an integrative epigenetic approach, we identified genes showing significant downregulation in EAC and displaying upregulation after 5-Aza-deoxycitidine. Among these genes, likely to be regulated by DNA methylation, NDRG4 was among the top 10 candidate genes. Analyses of TCGA (The Cancer Genome Atlas) and GEO (Gene Expression Omnibus) data sets and EAC tissue samples demonstrated that NDRG4 was significantly downregulated in EAC (p < 0.05). Using Pyrosequencing technology for quantification of DNA methylation, we detected that NDRG4 promoter methylation level was significantly higher in EAC tissue samples, as compared to normal esophagus samples (p < 0.01). A strong inverse correlation between NDRG4 methylation and its gene expression levels (r = −0.4, p < 0.01) was observed. Treatment with 5-Aza restored the NDRG4 expression, confirming that hypermethylation is a driving force for NDRG4 silencing in EAC. Pathway and gene set enrichment analyses of TCGA data suggested that NDRG4 is strongly associated with genes related to cell cycle regulation. Western blotting analysis showed significant downregulation of Cyclin D1, CDK4 and CDK6 in EAC cells after overexpression of NDRG4. Functionally, we found that the reconstitution of NDRG4 resulted in a significant reduction in tumor cell growth in two-dimensional (2D) and three-dimensional (3D) organotypic culture models and inhibited tumor cell proliferation as indicated by the EdU (5-ethynyl-2′-deoxyuridine) proliferation assay.

Pharmacological targeting and the diverse functions of the metastasis suppressor, NDRG1, in cancer

N-myc downstream regulated gene-1 (NDRG1) is a potent metastasis suppressor that is regulated by hypoxia, metal ions including iron, the free radical nitric oxide (NO^.), and various stress stimuli. This intriguing molecule exhibits diverse functions in cancer, inhibiting epithelial-mesenchymal transition (EMT), cell migration and angiogenesis by modulation of a plethora of oncogenes via cellular signaling. Thus, pharmacological targeting of NDRG1 signaling in cancer is a promising therapeutic strategy. Of note, novel anti-tumor agents of the di-2-pyridylketone thiosemicarbazone series, which exert the "double punch" mechanism by binding metal ions to form redox-active complexes, have been demonstrated to markedly up-regulate NDRG1 expression in cancer cells. This review describes the mechanisms underlying NDRG1 modulation by the thiosemicarbazones and the diverse effects NDRG1 exerts in cancer. As a major induction mechanism, iron depletion appears critical, with NO^. also inducing NDRG1 through its ability to bind iron and generate dinitrosyl-dithiol iron complexes, which are then effluxed from cells. Apart from its potent anti-metastatic role, several studies have reported a pro-oncogenic role of NDRG1 in a number of cancer-types. Hence, it has been suggested that NDRG1 plays pleiotropic roles depending on the cancer-type. The molecular mechanism(s) underlying NDRG1 pleiotropy remain elusive, but are linked to differential regulation of WNT signaling and potentially differential interaction with the tumor suppressor, PTEN. This review discusses NDRG1 induction mechanisms by metal ions and NO^. and both the anti- and possible pro-oncogenic functions of NDRG1 in multiple cancer-types and compares the opposite effects this protein exerts on cancer progression.

Combined targeting of MEK and the glucocorticoid receptor for the treatment of RAS-mutant multiple myeloma

BACKGROUND

Multiple myeloma (MM) remains incurable despite recent therapeutic advances. RAS mutations are frequently associated with relapsed/refractory disease. Efforts to target the mitogen-activated protein kinase (MAPK) pathway with the MEK inhibitor, trametinib (Tra) have been limited by toxicities and the development of resistance. Dexamethasone (Dex) is a corticosteroid commonly used in clinical practice, to enhance efficacy of anti-myeloma therapy. Therefore, we hypothesised that the combination of Tra and Dex would yield synergistic activity in RAS-mutant MM.

METHODS

The response of human MM cell lines to drug treatment was analysed using cell proliferation assays, Western blotting, Annexin V and propidium iodide staining by flow cytometry and reverse phase protein arrays. The efficacy of trametinib and dexamethasone treatment in the MM.1S xenograft model was assessed by measuring tumor volume over time.

RESULTS

The Tra/Dex combination demonstrated synergistic cytotoxicity in KRAS^G12A mutant lines MM.1S and RPMI-8226. The induction of apoptosis was associated with decreased MCL-1 expression and increased BIM expression. Reverse phase proteomic arrays revealed suppression of FAK, PYK2, FLT3, NDRG1 and 4EBP1 phosphorylation with the Tra/Dex combination. Notably, NDRG1 expression was associated with the synergistic response to Tra/Dex. MM cells were sensitive to PDK1 inhibition and IGF1-induced signalling partially protected from Tra/Dex treatment, highlighting the importance of this pathway. In the MM.1S tumor xenograft model, only the combination of Tra/Dex resulted in a significant inhibition of tumor growth.

CONCLUSIONS

Overall Tra/Dex demonstrates antiproliferative activity in RAS-mutant MM cell lines associated with suppression of pro-survival PDK1 signalling and engagement of apoptotic pathways. Our data support further investigation of this combination in RAS-mutant MM.

Metabolic reprogramming of fibro/adipogenic progenitors facilitates muscle regeneration

High-fat diet ameliorates muscle dystrophic phenotype by promoting the FAP-dependent myogenesis of satellite cells.

In Duchenne muscular dystrophy (DMD), the absence of the dystrophin protein causes a variety of poorly understood secondary effects. Notably, muscle fibers of dystrophic individuals are characterized by mitochondrial dysfunctions, as revealed by a reduced ATP production rate and by defective oxidative phosphorylation. Here, we show that in a mouse model of DMD (mdx), fibro/adipogenic progenitors (FAPs) are characterized by a dysfunctional mitochondrial metabolism which correlates with increased adipogenic potential. Using high-sensitivity mass spectrometry–based proteomics, we report that a short-term high-fat diet (HFD) reprograms dystrophic FAP metabolism in vivo. By combining our proteomic dataset with a literature-derived signaling network, we revealed that HFD modulates the β-catenin–follistatin axis. These changes are accompanied by significant amelioration of the histological phenotype in dystrophic mice. Transplantation of purified FAPs from HFD-fed mice into the muscles of dystrophic recipients demonstrates that modulation of FAP metabolism can be functional to ameliorate the dystrophic phenotype. Our study supports metabolic reprogramming of muscle interstitial progenitor cells as a novel approach to alleviate some of the adverse outcomes of DMD.

MicroRNA-regulated pathways of flow-stimulated angiogenesis and vascular remodeling in vivo

BACKGROUND

Vascular shear stress promotes endothelial cell sprouting in vitro. The impact of hemodynamic forces on microRNA (miRNA) and gene expression within growing vascular networks in vivo, however, remain poorly investigated. Arteriovenous (AV) shunts are an established model for induction of neoangiogenesis in vivo and can serve as a tool for analysis of hemodynamic effects on miRNA and gene expression profiles over time.

METHODS

AV shunts were microsurgically created in rats and explanted on postoperative days 5, 10 and 15. Neoangiogenesis was confirmed by histologic analysis and micro-computed tomography. MiRNA and gene expression profiles were determined in tissue specimens from AV shunts by microarray analysis and quantitative real-time polymerase chain reaction and compared with sham-operated veins by bioinformatics analysis. Changes in protein expression within AV shunt endothelial cells were determined by immunohistochemistry.

RESULTS

Samples from AV shunts exhibited a strong overexpression of proangiogenic cytokines, oxygenation-associated genes (HIF1A, HMOX1), and angiopoetic growth factors. Significant inverse correlations of the expressions of miR-223-3p, miR-130b-3p, miR-19b-3p, miR-449a-5p, and miR-511-3p which were up-regulated in AV shunts, and miR-27b-3p, miR-10b-5p, let-7b-5p, and let-7c-5p, which were down-regulated in AV shunts, with their predicted interacting targets C-X-C chemokine receptor 2 (CXCR2), interleukin-1 alpha (IL1A), ephrin receptor kinase 2 (EPHA2), synaptojanin-2 binding protein (SYNJ2BP), forkhead box C1 (FOXC1) were present. CXCL2 and IL1A overexpression in AV shunt endothelium was confirmed at the protein level by immunohistochemistry.

CONCLUSIONS

Our data indicate that flow-stimulated angiogenesis is determined by an upregulation of cytokines, oxygenation associated genes and miRNA-dependent regulation of FOXC1, EPHA2 and SYNJ2BP.

LSD1 mediates MYCN control of epithelial-mesenchymal transition through silencing of metastatic suppressor NDRG1 gene

Neuroblastoma (NB) with MYCN amplification is a highly aggressive and metastatic tumor in children. The high recurrence rate and resistance of NB cells to drugs urgently demands a better therapy for this disease. We have recently found that MYCN interacts with the lysine-specific demethylase 1 (LSD1), a histone modifier that participates in key aspects of gene transcription. In cancer cells, LSD1 contributes to the genetic reprogramming that underlies to Epithelial-Mesenchymal Transition (EMT) and tumor metastasis. Here, we show that LSD1 affects motility and invasiveness of NB cells by modulating the transcription of the metastasis suppressor NDRG1 (N-Myc Downstream-Regulated Gene 1). At mechanistic level, we found that LSD1 co-localizes with MYCN at the promoter region of the NDRG1 gene and inhibits its expression. Pharmacological inhibition of LSD1 relieves repression of NDRG1 by MYCN and affects motility and invasiveness of NB cells. These effects were reversed by overexpressing NDRG1. In NB tissues, high levels of LSD1 correlate with low levels of NDRG1 and reduced patients survival. Collectively, our findings elucidate a mechanism of how MYCN/LSD1 control motility and invasiveness of NB cells through transcription regulation of NDRG1 expression and suggest that pharmacological targeting of LSD1 represents a valuable approach for NB therapy.

The prognostic significance of N-myc downregulated gene 1 in lung adenocarcinoma

It has been reported that N-myc downstream regulated gene 1 (NDRG1) is related to the prognosis of non-small cell lung cancer (NSCLC), and associated with c-Myc degradation in NSCLC cell lines. However, the relationship of NDRG1 to prognosis or c-Myc expression in lung adenocarcinoma has not been well clarified. The present study was designed to investigate the prognostic significance of NDRG1 and/or c-Myc expression in lung adenocarcinoma using immunohistochemistry with a tissue microarray. We examined 184 lung adenocarcinomas and observed low expression of NDRG1 in adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA), whereas high expression of NDRG1 was seen in invasive adenocarcinoma. Each of the clinicopathological features except age was significantly correlated with NDRG1 expression. Kaplan-Meier curves indicated that high expression of NDRG1 was significantly correlated with poor prognosis in comparison with low expression (log-rank, P < 0.001). Univariate and multivariate analyses indicated that vascular invasion (P = 0.012), lymphatic permeation (P = 0.038), and NDRG1 expression (P = 0.026) were independent prognostic factors. Expression of NDRG1 and positivity for c-Myc were significantly correlated (P = 0.005). These findings indicate that NDRG1 expression is associated with both prognosis and c-Myc expression in lung adenocarcinoma.

N-Myc Downstream-Regulated Gene 1 Restricts Hepatitis C Virus Propagation by Regulating Lipid Droplet Biogenesis and Viral Assembly

Host cells harbor various intrinsic mechanisms to restrict viral infections as a first line of antiviral defense. Viruses have evolved various countermeasures against these antiviral mechanisms. Here we show that N-Myc downstream-regulated gene 1 (NDRG1) limits productive hepatitis C virus (HCV) infection by inhibiting viral assembly. Interestingly, HCV infection downregulates NDRG1 protein and mRNA expression. The loss of NDRG1 increases the size and number of lipid droplets, which are the sites of HCV assembly. HCV suppresses NDRG1 expression by upregulating MYC, which directly inhibits the transcription of NDRG1 The upregulation of MYC also leads to the reduced expression of the NDRG1-specific kinase serum/glucocorticoid-regulated kinase 1 (SGK1), resulting in a markedly diminished phosphorylation of NDRG1. The knockdown of MYC during HCV infection rescues NDRG1 expression and phosphorylation, suggesting that MYC regulates NDRG1 at both the transcriptional and posttranslational levels. Overall, our results suggest that NDRG1 restricts HCV assembly by limiting lipid droplet formation. HCV counteracts this intrinsic antiviral mechanism by downregulating NDRG1 via a MYC-dependent mechanism.IMPORTANCE Hepatitis C virus (HCV) is an enveloped single-stranded RNA virus that targets hepatocytes in the liver. HCV is a leading cause of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma, and estimates suggest a global prevalence of 2.35%. Up to 80% of acutely infected individuals will develop chronic infection, and as many as 5% eventually progress to liver cancer. An understanding of the mechanisms behind virus-host interactions and viral carcinogenesis is still lacking. The significance of our research is that it identifies a previously unknown relationship between HCV and a known tumor-associated gene. Furthermore, our data point to a new role for this gene in the liver and in lipid metabolism. Thus, HCV infection serves as a great biological model to advance our knowledge of liver functions and the development of liver cancer.

A Unique TGFB1-Driven Genomic Program Links Astrocytosis, Low-Grade Inflammation and Partial Demyelination in Spinal Cord Periplaques from Progressive Multiple Sclerosis Patients

We previously reported that, in multiple sclerosis (MS) patients with a progressive form of the disease, spinal cord periplaques extend distance away from plaque borders and are characterized by the co-occurrence of partial demyelination, astrocytosis and low-grade inflammation. However, transcriptomic analyses did not allow providing a comprehensive view of molecular events in astrocytes vs. oligodendrocytes. Here, we re-assessed our transcriptomic data and performed co-expression analyses to characterize astrocyte vs. oligodendrocyte molecular signatures in periplaques. We identified an astrocytosis-related co-expression module whose central hub was the astrocyte gene Cx43/GJA1 (connexin-43, also named gap junction protein α-1). Such a module comprised GFAP (glial fibrillary acidic protein) and a unique set of transcripts forming a TGFB/SMAD1/SMAD2 (transforming growth factor β/SMAD family member 1/SMAD family member 2) genomic signature. Partial demyelination was characterized by a co-expression network whose central hub was the oligodendrocyte gene NDRG1 (N-myc downstream regulated 1), a gene previously shown to be specifically silenced in the normal-appearing white matter (NAWM) of MS patients. Surprisingly, besides myelin genes, the NDRG1 co-expression module comprised a highly significant number of translation/elongation-related genes. To identify a putative cause of NDRG1 downregulation in periplaques, we then sought to identify the cytokine/chemokine genes whose mRNA levels inversely correlated with those of NDRG1. Following this approach, we found five candidate immune-related genes whose upregulation associated with NDRG1 downregulation: TGFB1(transforming growth factor β 1), PDGFC (platelet derived growth factor C), IL17D (interleukin 17D), IL33 (interleukin 33), and IL12A (interleukin 12A). From these results, we propose that, in the spinal cord periplaques of progressive MS patients, TGFB1 may limit acute inflammation but concurrently induce astrocytosis and an alteration of the translation/elongation of myelin genes in oligodendrocytes.

Novel Thiosemicarbazones Inhibit Lysine-Rich Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 (CEACAM1) Coisolated (LYRIC) and the LYRIC-Induced Epithelial-Mesenchymal Transition via Upregulation of N-Myc Downstream-Regulated Gene 1 (NDRG1)

Tumor necrosis factor α (TNFα) plays a vital role in cancer progression as it is associated with inflammation and promotion of cancer angiogenesis and metastasis. The effects of TNFα are mediated by its downstream target, the oncogene lysine-rich CEACAM1 coisolated protein (LYRIC, also known as metadherin or astrocyte elevated gene-1). LYRIC plays an important role in activating the nuclear factor-ĸB (NF-κB) signaling pathway, which controls multiple cellular processes, including proliferation, apoptosis, migration, etc. In contrast, the metastasis suppressor N-myc downstream regulated gene 1 (NDRG1) has the opposite effect on the NF-κB pathway, being able to inhibit NF-κB activation and reduce angiogenesis, proliferation, migration, and cancer cell invasion. These potent anticancer properties make NDRG1 an ideal therapeutic target. Indeed, a novel class of thiosemicarbazone anticancer agents that target this molecule has been developed; the lead agent, di-2-pyridylketone 4-cyclohexyl-4-methyl-3-thiosemicarbazone, has recently entered clinical trials for advanced and resistant cancers. To further elucidate the interaction between NDRG1 and oncogenic signaling, this study for the first time assessed the effects of NDRG1 on the tumorigenic properties of TNFα and its downstream target, LYRIC. We have demonstrated that NDRG1 inhibits the TNFα-mediated epithelial-to-mesenchymal transition. Further, NDRG1 also potently inhibited LYRIC expression, with a negative feedback loop existing between these two molecules. Examining the mechanism involved, we demonstrated that NDRG1 inhibited phosphatidylinositol 3-kinase/AKT signaling, leading to reduced levels of the LYRIC transcriptional activator, c-Myc. Finally, we demonstrated that novel thiosemicarbazones that upregulate NDRG1 also inhibit LYRIC expression, further highlighting their marked potential for cancer treatment.

Discovery of new substrates of the elongation factor-2 kinase suggests a broader role in the cellular nutrient response

Elongation Factor-2 Kinase (eEF2K) in an unusual mammalian enzyme that has one known substrate, elongation factor-2. It belongs to a class of kinases, called alpha kinases, that has little sequence identity to the >500 conventional protein kinases, but performs the same reaction and has similar catalytic residues. The phosphorylation of eEF2 blocks translation elongation, which is thought to be critical to regulating cellular energy usage. Here we report a system for discovering new substrates of alpha kinases and identify the first new substrates of eEF2K including AMPK and alpha4, and determine a sequence motif for the kinase that shows a requirement for threonine residues as the target of phosphorylation. These new substrates suggest that eEF2K has a more diverse role in regulating cellular energy usage that involves multiple pathways and regulatory feedback.

New Insights into Protein Hydroxylation and Its Important Role in Human Diseases

Protein hydroxylation is a post-translational modification catalyzed by 2-oxoglutarate-dependent dioxygenases. The hydroxylation modification can take place on various amino acids, including but not limited to proline, lysine, asparagine, aspartate and histidine. A classical example of this modification is hypoxia inducible factor alpha (HIF-α) prolyl hydroxylation, which affects HIF-α protein stability via the Von-Hippel Lindau (VHL) tumor suppressor pathway, a Cullin 2-based E3 ligase adaptor protein frequently mutated in kidney cancer. In addition to protein stability regulation, protein hydroxylation may influence other post-translational modifications or the kinase activity of the modified protein (such as Akt and DYRK1A/B). In other cases, protein hydroxylation may alter protein-protein interaction and its downstream signaling events in vivo (such as OTUB1, MAPK6 and eEF2K). In this review, we highlight the recently identified protein hydroxylation targets and their pathophysiological roles, especially in cancer settings. Better understanding of protein hydroxylation will help identify novel therapeutic targets and their regulation mechanisms to foster development of more effective treatment strategies for various human cancers.

Disrupted cooperation between transcription factors across diverse cancer types

Background

Transcription Factors (TFs), essential for many cellular processes, generally work coordinately to induce transcriptional change in response to internal and external signals. Disrupted cooperation between TFs, leading to dysregulation of target genes, contributes to the pathogenesis of many diseases, including cancer. Although the aberrant activation of individual TFs and the functional effects have been widely studied, the perturbation of TF cooperativity in cancer has rarely been explored.

Results

We used TF co-expression as proxy as cooperativity and performed a large-scale study on disrupted TF cooperation across seven cancer types. While the connectivity of downstream effectors, like metabolic genes and TF targets, were more or similarly disrupted than/with non-TFs, the cooperativity of TFs (upstream regulators) were consistently less disturbed in all studied cancer types. Highly coordinated TFs in normal, however, generally lost that cooperation in cancer. Although different types of cancer shared very few TF pairs with highly disrupted cooperation, the cooperativity of interferon regulatory factors (IRF) was highly disrupted in six cancer types. Specifically, the cooperativity of IRF8 was highly perturbed in lung cancer, which was further validated by two independent lung squamous cell carcinoma (LUSC) and lung adenocarcinoma (LUAD) datasets. More interestingly, the cooperativity of IRF8 was markedly associated with tumor progression and even contributed to the patient survival independent of tumor stage.

Conclusions

Our findings underscore the far more important role of TF cooperativity in tumorigenesis than previously appreciated. Disrupted cooperation of TFs provides potential clinical utility as prognostic markers for predicting the patient survival.

Electronic supplementary material

The online version of this article (doi:10.1186/s12864-016-2842-8) contains supplementary material, which is available to authorized users.

NDRG1 Controls Gastric Cancer Migration and Invasion through Regulating MMP-9

The purpose of this study is to detect the clinical significance of NDRG1 and its relationship with MMP-9 in gastric cancer metastatic progression. 101 cases of gastric cancer specimens were utilized to identify the protein expression of NDRG1 and MMP-9 by immunohistochemistry, their clinical significance was also analyzed. The suppression by siRNA-NDRG1 was employed to detect the role of NDRG1 in gastric cancer progression and its relationship with MMP-9. NDRG1 expression was correlated inversely with the degree of tumor cell differentiation (p < 0.01), invasion depth (p < 0.05), lymph node metastasis (p < 0.05) and TNM stage (p < 0.05), whereas MMP-9 was positive correlated with the degree of tumor cell differentiation (p < 0.01), lymph node metastasis (p < 0.05) and TNM stage (p < 0.05), but not correlated with invasion depth (p>0.05). Furthermore, cell proliferation and invasion effect were remarkably enhanced when NDRG1 was silencing, but MMP-9 expression was increased. NDRG1 silencing enhances gastric cancer cells progression through upregulating MMP-9. It suggests that NDRG1 may inhibit the metastasis of gastric cancer via regulating MMP-9.

DNA methylation patterns as noninvasive biomarkers and targets of epigenetic therapies in colorectal cancer

Aberrant DNA methylation is frequently detected in gastrointestinal tumors, and can therefore potentially be used to screen, diagnose, prognosticate, and predict colorectal cancers (CRCs). Although colonoscopic screening remains the gold standard for CRC screening, this procedure is invasive, expensive, and suffers from poor patient compliance. Methylated DNA is an attractive choice for a biomarker substrate because CRCs harbor hundreds of aberrantly methylated genes. Furthermore, abundance in extracellular environments and resistance to degradation and enrichment in serum, stool, and other noninvasive bodily fluids, allows quantitative measurements of methylated DNA biomarkers. This article describes the most important studies that investigated the efficacy of serum- or stool-derived methylated DNA as population-based screening biomarkers in CRC, details several mechanisms and factors that control DNA methylation, describes a better use of prevailing technologies that discover novel DNA methylation biomarkers, and illustrates the diversity of demethylating agents and their applicability toward clinical impact.

NDRG1 promotes the multidrug resistance of neuroblastoma cells with upregulated expression of drug resistant proteins

BACKGROUND

Resistance to chemotherapeutic drugs and recurrence are two major causes of poor prognosis in many tumors including neuroblastoma. This study aimed to investigate the effect of the elevated intracellular NDRG1 expression on drug resistance of human neuroblastoma cells to chemotherapy, for exploring novel approaches for biotherapy of neuroblastoma.

METHODS

Human neuroblastoma KP-N-Ns cell lines were transfected with the lentivirus vector containing human NDRG1 cDNA, with empty vector-transfected or blank cells as controls. Transfection status was confirmed under fluorescence microscope, while PCR assay and western blot analysis were performed to determine the expression changes. MTT and TUNEL assays were used to detect the resistance of the cells to anticancer drugs, including vincristine, cyclophosphamide and so on. Additionally, the expression of drug resistant proteins was detected.

RESULTS

Stable lentiviral transfection cell line was successfully established with significantly upregulated NDRG1 expression. MTT assay revealed greater cell growth under NDRG1 overexpression with drugs stimulation, as compared to controls. TUNEL assay also showed less apoptosis of NDRG1 overexpressing cells than those of controls when exposed to these drugs, suggesting the increasing drug resistance through NDRG1 overexpression. Besides, the expression of MDR, LRP-1 and MRP-1 was also increased in NDRG1 overexpressing cells, implying NDRG1-mediated pathways in multidrug resistance of neuroblastoma.

CONCLUSION

NDRG1 could increase the resistance of neuroblastoma cells to chemotherapeutic drugs, with its positive regulation on drug resistant proteins. This study provided new insights for exploring the mechanism of the resistance to chemotherapeutic drugs and also novel approach for biotherapy in neuroblastoma.

NDRG1 expression is related to the progression and prognosis of gastric cancer patients through modulating proliferation, invasion and cell cycle of gastric cancer cells

N-myc downstream-regulated gene 1 (NDRG1) has been proposed as a tumor suppressor gene in many different types of tumors, but its potential function and corresponding mechanism are not yet fully elucidated. This study aims to detect the possible function of NDRG1 in gastric cancer progression. In this study, 112 paired gastric cancer tissues and corresponding nonmalignant gastric tissues were utilized to identify the differential protein expression of NDRG1 by immunohistochemistry and its clinical significance was analyzed. Furthermore, 49 of 112 paired gastric specimens were used to detect the differential mRNA expression by real-time PCR. The over expression of NDRG1 in human gastric cancer cell line AGS by PcDNA3.1-NDRG1 transfection was utilized to detect the role of NDRG1 in regulating the biological behavior of gastric cancer. NDRG1 expression was significantly decreased in primary gastric cancer tissues, compared with its corresponding nonmalignant gastric tissues (p < 0.05), and its decreased expression was significantly associated with lymph node metastasis (p < 0.01), invasion depth (p < 0.01) and differentiation (p < 0.05). Additionally, the overall survival rate of gastric cancer patients with high expression of NDRG1 was higher than those with low expression during the follow-up period. NDRG1 overexpression suppressed cells proliferation, invasion and induced a G1 cell cycle arrest in gastric cancer. Furthermore, the down-regulation of NDRG1 in gastric cancer metastatic progression was correlated to E-cadherin and MMP-9. Our results verify that NDRG1 acts as a tumor suppressor gene and may play an important role in the metastasis progression and prognosis of gastric cancer.

Molecular functions of the iron-regulated metastasis suppressor, NDRG1, and its potential as a molecular target for cancer therapy

N-myc down-regulated gene 1 (NDRG1) is a known metastasis suppressor in multiple cancers, being also involved in embryogenesis and development, cell growth and differentiation, lipid biosynthesis and myelination, stress responses and immunity. In addition to its primary role as a metastasis suppressor, NDRG1 can also influence other stages of carcinogenesis, namely angiogenesis and primary tumour growth. NDRG1 is regulated by multiple effectors in normal and neoplastic cells, including N-myc, histone acetylation, hypoxia, cellular iron levels and intracellular calcium. Further, studies have found that NDRG1 is up-regulated in neoplastic cells after treatment with novel iron chelators, which are a promising therapy for effective cancer management. Although the pathways by which NDRG1 exerts its functions in cancers have been documented, the relationship between the molecular structure of this protein and its functions remains unclear. In fact, recent studies suggest that, in certain cancers, NDRG1 is post-translationally modified, possibly by the activity of endogenous trypsins, leading to a subsequent alteration in its metastasis suppressor activity. This review describes the role of this important metastasis suppressor and discusses interesting unresolved issues regarding this protein.

Proteomic snapshot of breast cancer cell cycle: G1/S transition point

The biological processes that unfold during the G1-phase of the cell cycle are dependent on extracellular mitogenic factors that signal the cell to enter a state of quiescence, or commit to a cell-cycle round by passing the restriction point (R-point) and enter the S-phase. Unlike normal cells, cancer cells evolved the ability to evade the R-point and continue through the cell cycle even in the presence of extensive DNA damage or absence of mitogenic signals. The purpose of this study was to perform a quantitative proteomic evaluation of the biological processes that are responsible for driving MCF-7 breast cancer cells into division even when molecular checkpoints such as the G1/S R-point are in place. Nuclear and cytoplasmic fractions of the G1 and S cell-cycle phases were analyzed by LC-MS/MS to result in the confident identification of more than 2700 proteins. Statistical evaluation of the normalized data resulted in the selection of proteins that displayed twofold or more change in spectral counts in each cell state. Pathway mapping, functional annotation clustering, and protein interaction network analysis revealed that the top-scoring clusters that could play a role in overriding the G1/S transition point included DNA damage response, chromatin remodeling, transcription/translation regulation, and signaling proteins.

Oncogenic but non-essential role of N-myc downstream regulated gene 1 in the progression of esophageal squamous cell carcinoma

N-myc downstream regulated gene 1 (NDRG1/Cap43/Drg-1) has previously been shown to be dysregulated in esophageal squamous cell carcinoma (ESCC). In this study, we investigated the role of NDRG1 in the neoplastic progression of ESCC using ectopic gain-of-function and loss-of-function approaches. Stable transfectants of the KYSE30 ESCC cell line with altered NDRG1 levels were generated by lentiviral transduction. Although no measurable effects on in vitro cell proliferation were observed with altered NDRG1 expression, the ectopic overexpression of NDRG1 was positively linked to recognized markers of metastasis, angiogenesis and apoptotic evasion. Accordingly, in the nude mouse xenograft model system, NDRG1 overexpression promoted the in vivo growth of KYSE30 derived xenografts, which could be attributed to the reduced apoptotic and enhanced angiogenic activities associated with this gene. These processes were mediated in part by increased NFκB activity in NDRG1 overexpressing cells. Nevertheless, no significant phenotypic changes were observed in response to NDRG1 knock-down, suggesting that this gene might not be essential for the neoplastic progression of ESCC. Taken together, our results suggest that NDRG1 may play positive but dispensable roles in the progression of esophageal squamous cell carcinoma.

p53, SKP2, and DKK3 as MYCN Target Genes and Their Potential Therapeutic Significance

Neuroblastoma is the most common extra-cranial solid tumor of childhood. Despite significant advances, it currently still remains one of the most difficult childhood cancers to cure, with less than 40% of patients with high-risk disease being long-term survivors. MYCN is a proto-oncogene implicated to be directly involved in neuroblastoma development. Amplification of MYCN is associated with rapid tumor progression and poor prognosis. Novel therapeutic strategies which can improve the survival rates whilst reducing the toxicity in these patients are therefore required. Here we discuss genes regulated by MYCN in neuroblastoma, with particular reference to p53, SKP2, and DKK3 and strategies that may be employed to target them.

Prognostic significance of NDRG1 expression in oral and oropharyngeal squamous cell carcinoma

Human N-myc downstream-regulated gene 1 (NDRG1) is a metastasis suppressor gene with several potential functions, including cell differentiation, cell cycle regulation and response to hormones, nickel and stress. The purpose of this study was to investigate the immunoexpression of NDRG1 in oral and oropharyngeal squamous cell carcinomas searching for its role in the clinical course of these tumors. We investigated immunohistochemical expression of NDRG1 protein in 412 tissue microarray cores of tumor samples from 103 patients with oral and oropharyngeal squamous cell carcinomas and in 110 paraffin-embedded surgical margin sections. The results showed NDRG1 up-regulation in 101/103 (98.1 %) tumor samples, but no expression in any normal tissue sample. Western blot assays confirmed the immunohistochemical findings, suggesting that lower levels of NDRG1 are associated with a high mortality rate. NDRG1 overexpression was related to long-term specific survival (HR = 0.38; p = 0.009), whereas the presence of lymph-node metastasis showed the opposite association with survival (HR = 2.45; p = 0.013). Our findings reinforce the idea that NDRG1 plays a metastasis suppressor role in oral and oropharyngeal squamous cell carcinomas and may be a useful marker for these tumors.

NDRG2 in rat liver regeneration: role in proliferation and apoptosis

Liver regeneration is a complex process that is orchestrated by the precise interplay of cell proliferation, differentiation control, and molecular pathways, but this complicated molecular signaling network is not fully understood. In this study, we showed that N-Myc downstream-regulated gene 2 (NDRG2) is involved in this process. The mRNA and protein levels of NDRG2 were strongly reduced when liver regeneration reached a peak of activity. In addition, we found that rat NDRG2 expression and C-Myc expression were inversely correlated during this process. A low level of NDRG2 was observed as the C-Myc expression increased during regeneration. Moreover, a dramatic cell cycle arrest was found in normal rat liver-derived BRL cells 48 hours after being infected by adenoviral vectors expressing rat NDRG2. Meanwhile, the apoptotic rates were increased from 9.4% in control group to 64.7% in adenoviral vectors expressing rat NDRG2 group. These phenomena could also be observed in BRL 3A and L-02 cells. Further analysis revealed that NDRG2 overexpression may mediate the antiproliferative effect by inducing p53 and p21 regulated Bax/Bcl-2 increase and cyclin E-Cdk2 inhibition. In conclusion, our findings point to physiological roles for NDRG2 in liver regeneration.

The levels of hypoxia-regulated microRNAs in plasma of pregnant women with fetal growth restriction

MicroRNAs (miRNAs) are short non-coding RNAs that regulate gene expression at the post-transcriptional level. While mostly intracellular, a portion of cellular miRNAs is released to the circulation and their level in the plasma is altered in certain pathological conditions such as cancer, and also during pregnancy. We examined the circulating levels of a set of trophoblastic miRNAs, which we recently found to be regulated by hypoxia, in the plasma of pregnant women with fetal growth restriction (FGR). Pregnancy was associated with increased plasma levels of several placenta-specific miRNAs, compared to non-pregnant controls. Among pregnant women, the overall levels of miRNA species that we analyzed were increased by 1.84-fold (p < or = 0.01) in plasma of women with pregnancies complicated by FGR, but decreased in FGR placentas by 24% (p < or = 0.01) compared to values from uncomplicated pregnancies. Together, our results show that plasma concentration of miRNAs is regulated in pregnancy, and that FGR is associated with increased circulating miRNA levels, highlighting the need to explore plasma miRNAs as potential biomarkers for placental diseases.

Epigenetic regulation affects N-myc downstream-regulated gene 1 expression indirectly in pancreatic cancer cells

OBJECTIVES

N-myc downstream-regulated gene 1 (NDRG1), important in tumor growth and metastasis, has recently gained interest as a potential therapeutic target. Loss of NDRG1 expression is generally associated with poor clinical outcome in pancreatic cancer (PaCa) patients. As the NDRG1 gene possesses a large promoter CpG island, we sought to determine whether its repression is epigenetically mediated in PaCa cells.

METHODS

Pancreatic cancer cells were treated with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine and the histone deacetylase inhibitor trichostatin A. Promoter methylation was assessed by genomic bisulfite sequencing and by combined bisulfite restriction analyses.

RESULTS

Treatment with 5-aza-2'-deoxycytidine and trichostatin A enhanced NDRG1 protein expression, implicating epigenetic regulation of NDRG1. However, there was no significant DNA methylation of the NDRG1 promoter CpG island, as determined by genomic bisulfite sequencing of HPAF-II cells. We further confirmed the lack of promoter methylation in 6 PaCa cell lines by combined bisulfite restriction analyses.

CONCLUSIONS

These findings indicate that NDRG1 gene reactivation in PaCa cell lines by pharmacologic reversal of DNA methylation and histone deacetylation occurs via an indirect mechanism. This may occur via the altered expression of genes involved in the regulation of NDRG1 transcription or NDRG1 protein stability in PaCa cells.

Cholesterol and phytosterols differentially regulate the expression of caveolin 1 and a downstream prostate cell growth-suppressor gene

BACKGROUND

The purpose of our study was to show the distinction between the apoptotic and anti-proliferative signaling of phytosterols and cholesterol-enrichment in prostate cancer cell lines, mediated by the differential transcription of caveolin-1, and N-myc downstream-regulated gene 1 (NDRG1), a pro-apoptotic androgen-regulated tumor suppressor.

METHODS

PC-3 and DU145 cells were treated with sterols (cholesterol and phytosterols) for 72h, followed by trypan blue dye-exclusion measurement of necrosis and cell growth measured with a Coulter counter. Sterol induction of cell growth-suppressor gene expression was evaluated by mRNA transcription using RT-PCR, while cell cycle analysis was performed by FACS analysis. Altered expression of Ndrg1 protein was confirmed by Western blot analysis. Apoptosis was evaluated by real time RT-PCR amplification of P53, Bcl-2 gene and its related pro- and anti-apoptotic family members.

RESULTS

Physiological doses (16microM) of cholesterol and phytosterols were not cytotoxic in these cells. Cholesterol-enrichment promoted cell growth (P<0.05), while phytosterols significantly induced growth-suppression (P<0.05) and apoptosis. Cell cycle analysis showed that contrary to cholesterol, phytosterols decreased mitotic subpopulations. We demonstrated for the first time that cholesterols concertedly attenuated the expression of caveolin-1 (cav-1) and NDRG1 genes in both prostate cancer cell lines. Phytosterols had the opposite effect by inducing overexpression of cav-1, a known mediator of androgen-dependent signals that presumably control cell growth or apoptosis.

CONCLUSIONS

Cholesterol and phytosterol treatment differentially regulated the growth of prostate cancer cells and the expression of p53 and cav-1, a gene that regulates androgen-regulated signals. These sterols also differentially regulated cell cycle arrest, downstream pro-apoptotic androgen-regulated tumor suppressor, NDRG1 suggesting that cav-1 may mediate pro-apoptotic NDRG1 signals. Elucidation of the mechanism for sterol modulation of growth and apoptosis signaling may reveal potential targets for cancer prevention and/or chemotherapeutic intervention. Sterol regulation of NDRG1 transcription suggests its potential as biomarker for prediction of neoplasms that would be responsive to chemoprevention by phytosterols.

T-box 2 represses NDRG1 through an EGR1-dependent mechanism to drive the proliferation of breast cancer cells

T-box 2 (TBX2) is a transcription factor involved in mammary development and is known to be overexpressed in a subset of aggressive breast cancers. TBX2 has previously been shown to repress growth control genes such as p14(ARF) and p21(WAF1/cip1). In this study we show that TBX2 drives proliferation in breast cancer cells and this is abrogated after TBX2 small interfering RNA (siRNA) knockdown or after the expression of a dominant-negative TBX2 protein. Using microarray analysis we identified a large cohort of novel TBX2-repressed target genes including the breast tumour suppressor NDRG1 (N-myc downregulated gene 1). We show that TBX2 targets NDRG1 through a previously undescribed mechanism involving the recruitment of early growth response 1 (EGR1). We show EGR1 is required for the ability of TBX2 to repress NDRG1 and drive cell proliferation. We show that TBX2 interacts with EGR1 and that TBX2 requires EGR1 to target the NDRG1 proximal promoter. Abrogation of either TBX2 or EGR1 expression is accompanied by the upregulation of cell senescence and apoptotic markers. NDRG1 can recapitulate these effects when transfected into TBX2-expressing cells. Together, these data identify a novel mechanism for TBX2-driven oncogenesis and highlight the importance of NDRG1 as a growth control gene in breast tissue.