FOXD3 is a novel tumor suppressor that affects growth, invasion, metastasis and angiogenesis of neuroblastoma

Transcriptional repression upon S phase entry protects genome integrity in pluripotent cells

Coincident transcription and DNA replication causes replication stress and genome instability. Rapidly dividing mouse pluripotent stem cells are highly transcriptionally active and experience elevated replication stress, yet paradoxically maintain genome integrity. Here, we study FOXD3, a transcriptional repressor enriched in pluripotent stem cells, and show that its repression of transcription upon S phase entry is critical to minimizing replication stress and preserving genome integrity. Acutely deleting Foxd3 leads to immediate replication stress, G2/M phase arrest, genome instability and p53-dependent apoptosis. FOXD3 binds near highly transcribed genes during S phase entry, and its loss increases the expression of these genes. Transient inhibition of RNA polymerase II in S phase reduces observed replication stress and cell cycle defects. Loss of FOXD3-interacting histone deacetylases induces replication stress, while transient inhibition of histone acetylation opposes it. These results show how a transcriptional repressor can play a central role in maintaining genome integrity through the transient inhibition of transcription during S phase, enabling faithful DNA replication.

MicroRNAs as the critical regulators of Forkhead box protein family during gynecological and breast tumor progression and metastasis

Gynecological and breast tumors are one of the main causes of cancer-related mortalities among women. Despite recent advances in diagnostic and therapeutic methods, tumor relapse is observed in a high percentage of these patients due to the treatment failure. Late diagnosis in advanced tumor stages is one of the main reasons for the treatment failure and recurrence in these tumors. Therefore, it is necessary to assess the molecular mechanisms involved in progression of these tumors to introduce the efficient early diagnostic markers. Fokhead Box (FOX) is a family of transcription factors with a key role in regulation of a wide variety of cellular mechanisms. Deregulation of FOX proteins has been observed in different cancers. MicroRNAs (miRNAs) as a group of non-coding RNAs have important roles in post-transcriptional regulation of the genes involved in cellular mechanisms. They are also the non-invasive diagnostic markers due to their high stability in body fluids. Considering the importance of FOX proteins in the progression of breast and gynecological tumors, we investigated the role of miRNAs in regulation of the FOX proteins in these tumors. MicroRNAs were mainly involved in progression of these tumors through FOXM, FOXP, and FOXO. The present review paves the way to suggest a non-invasive diagnostic panel marker based on the miRNAs/FOX axis in breast and gynecological cancers.

Specific gene expression signatures of low grade meningiomas

Introduction

Meningiomas are the most common primary central nervous system (CNS) tumors in adults, representing approximately one-third of all primary adult CNS tumors. Although several recent publications have proposed alternative grading systems of meningiomas that incorporate genomic and/or epigenomic data to better predict meningioma recurrence and progression-free survival, our understanding of driving forces of meningioma development is still limited.

Objective

To define gene expression signatures of the most common subtypes of meningiomas to better understand cellular processes and signaling pathways specific for each tumor genotype.

Methods

We used RNA sequencing (RNA-seq) to determine whole transcriptome profiles of twenty meningiomas with genomic alterations including NF2 inactivation, loss of chr1p, and missense mutations in TRAF7, AKT1 and KLF4.

Results

The analysis revealed that meningiomas with NF2 gene inactivation expressed higher levels of BCL2 and GLI1 compared with tumors harboring TRAF7 missense mutations. Moreover, NF2 meningiomas were subdivided into two distinct groups based on additional loss of chr1p. NF2 tumors with intact chr1p were characterized by the high expression of tumor suppressor PTCH2 compared to NF2 tumors with chr1p loss. Taken together with the high expression of BCL2 and GLI1, these results suggest that activation of Sonic Hedgehog pathway may contribute to NF2 meningioma development. In contrast, NF2 tumors with chr1p loss expressed high levels of transcription factor FOXD3 and its antisense RNA FOXD3-AS1. Examination of TRAF7 tumors demonstrated that TRAF7 regulates a number of biomechanically responsive genes (KRT6a, KRT16, IL1RL1, and AQP3 among others). Interestingly, AKT1 and KLF4 meningiomas expressed genes specific for PI3K/AKT signaling pathway, suggesting overlapping gene signatures between the two subtypes. In addition, KLF4 meningiomas had high expression of carcinoembryonic antigen family members CEACAM6 and CEACAM5.

Conclusions

Each group of meningiomas displayed a unique gene expression signature suggesting signaling pathways potentially implicated in tumorigenesis. These findings will improve our understanding of meningioma tumorigenesis and prognosis.

FOXD3 suppresses epithelial-mesenchymal transition through direct transcriptional promotion of SMAD7 in esophageal squamous cell carcinoma

The transcription factor forkhead box D3 (FOXD3) is an important member of the FOX family, which can maintain the pluripotent properties of cell clusters, neural crest, and trophoblastic progenitor cells in vivo. It has been shown that FOXD3 could affect proliferation, migration, and angiogenesis of various tumors and its deletion and overexpression in organisms will undoubtedly have important influence on the change of cell fate and the occurrence of tumors. However, the underlying functions and molecular mechanisms of FOXD3 in esophageal squamous cell carcinoma (ESCC) have not been fully clarified. According to the present study, the expression levels and functional roles of FOXD3 were investigated, and its prognostic value and molecular mechanisms in tumorigenesis and progression of ESCC were clarified. The expression level of FOXD3 was significantly downregulated in ESCC tissues and cell lines, and correlated with gender, family history of upper gastrointestinal cancer, TNM stage, depth of invasion, lymph node metastasis, and ESCC patients' survival. Moreover, FOXD3 inhibited cells migration and invasion as well as participated in TGF-β1 induced epithelial-mesenchymal transition process. Furthermore, a positive correlation between FOXD3 and SMAD family member 7 (SMAD7) was explored in ESCC. FOXD3 could directly bind to promoter regions of SMAD7 gene, leading to transcriptional promotion of SMAD7 in human esophageal cancer cells. Taken together, FOXD3 may play a tumor suppressor role in ESCC and may be applied as a new therapeutic target and prognostic marker for ESCC.

Mechanisms involved in selecting and maintaining neuroblastoma cancer stem cell populations, and perspectives for therapeutic targeting

Pediatric neuroblastomas (NBs) are heterogeneous, aggressive, therapy-resistant embryonal tumours that originate from cells of neural crest (NC) origin and in particular neuroblasts committed to the sympathoadrenal progenitor cell lineage. Therapeutic resistance, post-therapeutic relapse and subsequent metastatic NB progression are driven primarily by cancer stem cell (CSC)-like subpopulations, which through their self-renewing capacity, intermittent and slow cell cycles, drug-resistant and reversibly adaptive plastic phenotypes, represent the most important obstacle to improving therapeutic outcomes in unfavourable NBs. In this review, dedicated to NB CSCs and the prospects for their therapeutic eradication, we initiate with brief descriptions of the unique transient vertebrate embryonic NC structure and salient molecular protagonists involved NC induction, specification, epithelial to mesenchymal transition and migratory behaviour, in order to familiarise the reader with the embryonic cellular and molecular origins and background to NB. We follow this by introducing NB and the potential NC-derived stem/progenitor cell origins of NBs, before providing a comprehensive review of the salient molecules, signalling pathways, mechanisms, tumour microenvironmental and therapeutic conditions involved in promoting, selecting and maintaining NB CSC subpopulations, and that underpin their therapy-resistant, self-renewing metastatic behaviour. Finally, we review potential therapeutic strategies and future prospects for targeting and eradication of these bastions of NB therapeutic resistance, post-therapeutic relapse and metastatic progression.

CO2 Pneumoperitoneum Effects on Molecular Markers of Tumor Invasiveness in SH-SY5Y Neuroblastoma Cells

INTRODUCTION

 CO₂ pneumoperitoneum can influence the biological behavior of neuroblastoma (NB). Angiogenesis and genetic features are responsible for malignant phenotype of this tumor. We examined the CO₂ effects on N-Myc, vascular endothelial growth factor (VEGF), and matrix metalloproteinase-2 (MMP-2) expression as critical biomarkers of tumor invasiveness, in NB cells without N-Myc amplification.

MATERIALS AND METHODS

 SH-SY5Y cells were exposed to CO₂ (100%) at 15 mm Hg pressure for 4 hours and then moved to normal condition for 24 hours. Control cells were incubated with 5% CO₂ for the same time. In control and CO₂-exposed cells, the messenger ribonucleic acid (mRNA) levels of hypoxia-inducible factor (HIF)-1α, HIF-2α, VEGF-A, and MMP-2 were quantified by real-time polymerase chain reaction. N-Myc expression was evaluated by Western blot analysis.

RESULTS

 The exposure to 15 mm Hg CO₂ (100%) for 4 hours induced an increase in HIF-1α, but not in HIF-2α, mRNA levels. No differences were observed in N-Myc expression between exposed and control cells at each incubation time. Similarly, no significant differences were found for VEGF-A and MMP-2 transcript levels. In CO₂ exposed cells, we observed only a slight increase in both VEGF-A and MMP-2 mRNA levels after 4 and 24 hours in comparison to controls.

CONCLUSION

 In our study, the hypoxic environment induced by CO₂ exposure does not affect the expression of critical biomarkers of NB aggressiveness, such as N-Myc, VEGF, and MMP-2, in human SH-SY5Y NB cells without N-Myc amplification. These data suggest that CO₂ pneumoperitoneum might not adversely impact NB cell invasiveness; however, it is necessary to evaluate these effects in others in vitro and in vivo models.

Long Noncoding RNA NHEG1 Drives β-Catenin Transactivation and Neuroblastoma Progression through Interacting with DDX5

Recent studies suggest that long noncoding RNAs (lncRNAs) play essential roles in tumor progression. However, the functional roles and underlying mechanisms of lncRNAs in neuroblastoma (NB), the most common malignant solid tumor in pediatric population, still remain elusive. Herein, through integrating analysis of a public RNA sequencing dataset, neuroblastoma highly expressed 1 (NHEG1) was identified as a risk-associated lncRNA, contributing to an unfavorable outcome of NB. Depletion of NHEG1 led to facilitated differentiation and decreased growth and aggressiveness of NB cells. Mechanistically, NHEG1 bound to and stabilized DEAD-box helicase 5 (DDX5) protein through repressing proteasome-mediated degradation, resulting in β-catenin transactivation that altered target gene expression associated with NB progression. We further determined a lymphoid enhancer binding factor 1 (LEF1)/transcription factor 7-like 2 (TCF7L2)/NHEG1/DDX5/β-catenin axis with a positive feedback loop and demonstrated that NHEG1 harbored oncogenic properties via its interplay with DDX5. Administration of small interfering RNAs against NHEG1 or DDX5 reduced tumor growth and prolonged survival of nude mice bearing xenografts. High NHEG1 or DDX5 expression was associated with poor survival of NB patients. These results indicate that lncRNA NHEG1 exhibits oncogenic activity that affects NB progression via stabilizing the DDX5 protein, which might serve as a potential therapeutic target for NB.

FOXD3, frequently methylated in colorectal cancer, acts as a tumor suppressor and induces tumor cell apoptosis under ER stress via p53

Forkhead box D3 (FOXD3), an important member of the forkhead box transcription factor family, has many biological functions. However, the role and signaling pathways of FOXD3 in colorectal cancer (CRC) are still unclear. We examined FOXD3 expression and methylation in normal colon mucosa, CRC cell lines and primary tumors by reverse transcription–polymerase chain reaction, methylation-specific PCR and bisulfite genomic sequencing. We also evaluated its tumor-suppressive function by examining its modulation of apoptosis under endoplasmic reticulum (ER) stress in CRC cells. The FOXD3 target signal pathway was identified by western blotting, immunofluorescence and chromatin immunoprecipitation. We found that FOXD3 was frequently methylated and silenced in CRC cell lines and was downregulated in CRC tissues compared with paired adjacent non-tumor tissues. Meanwhile, low FOXD3 protein expression was significantly correlated with poor histopathological grading, lymph node metastasis and poor prognosis of patients, indicating its potential as a tumor marker that may be of potential value as a therapeutic target for CRC. Moreover, restoration of FOXD3 expression inhibited the proliferation and migration of tumor cells. FOXD3 also increased mitochondrial apoptosis through the unfolded protein response under ER stress. Furthermore, we found that FOXD3 could bind directly to the promoter of p53 and enhance its expression. Knockdown of p53 impaired the effect of apoptosis induced by FOXD3. In conclusion, we showed for the first time that FOXD3, which is frequently methylated in CRC, acted as a tumor suppressor inducing tumor cell apoptosis under ER stress via p53.

Nervous NDRGs: the N-myc downstream-regulated gene family in the central and peripheral nervous system

The N-Myc downstream-regulated gene (NDRG) family consists of four members (NDRG1, NDRG2, NDRG3, NDRG4) that are differentially expressed in various organs and function in important processes, like cell proliferation and differentiation. In the last couple of decades, interest in this family has risen due to its connection with several disorders of the nervous system including Charcot-Marie-Tooth disease and dementia, as well as nervous system cancers. By combining a literature review with in silico data analysis of publicly available datasets, such as the Mouse Brain Atlas, BrainSpan, the Genotype-Tissue Expression (GTEx) project, and Gene Expression Omnibus (GEO) datasets, this review summarizes the expression and functions of the NDRG family in the healthy and diseased nervous system. We here show that the NDRGs have a differential, relatively cell type-specific, expression pattern in the nervous system. Even though NDRGs share functionalities, like a role in vesicle trafficking, stress response, and neurite outgrowth, other functionalities seem to be unique to a specific member, e.g., the role of NDRG1 in myelination. Furthermore, mutations, phosphorylation, or changes in expression of NDRGs are related to nervous system diseases, including peripheral neuropathy and different forms of dementia. Moreover, NDRG1, NDRG2, and NDRG4 are all involved in cancers of the nervous system, such as glioma, neuroblastoma, or meningioma. All in all, our review elucidates that although the NDRGs belong to the same gene family and share some functional features, they should be considered unique in their expression patterns and functional importance for nervous system development and neuronal diseases.

Differential responses of epithelial cells from urinary and biliary tract to eggs of Schistosoma haematobium and S. mansoni

Chronic urogenital schistosomiasis can lead to squamous cell carcinoma of the bladder. The International Agency for Research on Cancer classifies the infection with S. haematobium as a group 1 carcinogen, a definitive cause of cancer. By contrast, hepatointestinal schistosomiasis due to the chronic infection with S. mansoni or S. japonicum associated with liver periportal fibrosis, does not apparently lead to malignancy. The effects of culturing human epithelial cells, HCV29, established from normal urothelium, and H69, established from cholangiocytes, in the presence of S. haematobium or S. mansoni eggs were investigated. Cell growth of cells co-cultured with schistosome eggs was monitored in real time, and gene expression analysis of oncogenesis, epithelial to mesenchymal transition and apoptosis pathways was undertaken. Schistosome eggs promoted proliferation of the urothelial cells but inhibited growth of cholangiocytes. In addition, the tumor suppressor P53 pathway was significantly downregulated when exposed to schistosome eggs, and downregulation of estrogen receptor was predicted in urothelial cells exposed only to S. haematobium eggs. Overall, cell proliferative responses were influenced by both the tissue origin of the epithelial cells and the schistosome species.

Dynamics of Minimal Residual Disease in Neuroblastoma Patients

Neuroblastoma is a common extracranial solid tumor of neural crest (NC) origin that accounts for up to 15% of all pediatric cancer deaths. The disease arises from a transient population of NC cells that undergo an epithelial-mesenchymal transition (EMT) and generate diverse cell-types and tissues. Patients with neuroblastoma are characterized by their extreme heterogeneity ranging from spontaneous regression to malignant progression. More than half of newly diagnosed patients present highly metastatic tumors and are stratified into a high-risk group with dismal outcome. As many as 20% of high-risk patients have residual disease that is refractory or progressive during induction chemotherapy. Although a majority of high-risk patients achieve remission, larger part of those patients has minimal residual disease (MRD) that causes relapse even after additional consolidation therapy. MRD is composed of drug-resistant tumor cells and dynamically presented as cancer stem cells (CSCs) in residual tumors, circulating tumor cells (CTCs) in peripheral blood (PB), and disseminated tumor cells (DTCs) in bone marrow (BM) and other metastatic sites. EMT appears to be a key mechanism for cancer cells to acquire MRD phenotypes and malignant aggressiveness. Due to the restricted availability of residual tumors, PB and BM have been used to isolate and analyze CTCs and DTCs to evaluate MRD in cancer patients. In addition, recent technical advances make it possible to use circulating tumor DNA (ctDNA) shed from tumor cells into PB for MRD evaluation. Because MRD can be detected by tumor-specific antigens, genetic or epigenetic changes, and mRNAs, numerous assays using different methods and samples have been reported to detect MRD in cancer patients. In contrast to the tumor-specific gene-rearrangement-positive acute lymphoblastic leukemia (ALL) and the oncogenic fusion-gene-positive chronic myelogenous leukemia (CML) and several solid tumors, the clinical significance of MRD remains to be established in neuroblastoma. Given the extreme heterogeneity of neuroblastoma, dynamics of MRD in neuroblastoma patients will hold a key to the clinical validation. In this review, we summarize the biology and detection methods of cancer MRD in general and evaluate the available assays and clinical significance of neuroblastoma MRD to clarify its dynamics in neuroblastoma patients.

Hijacking of Embryonic Programs by Neural Crest-Derived Neuroblastoma: From Physiological Migration to Metastatic Dissemination

In the developing organism, complex molecular programs orchestrate the generation of cells in adequate numbers, drive them to migrate along the correct pathways towards appropriate territories, eliminate superfluous cells, and induce terminal differentiation of survivors into the appropriate cell-types. Despite strict controls constraining developmental processes, malignancies can emerge in still immature organisms. This is the case of neuroblastoma (NB), a highly heterogeneous disease, predominantly affecting children before the age of 5 years. Highly metastatic forms represent half of the cases and are diagnosed when disseminated foci are detectable. NB arise from a transient population of embryonic cells, the neural crest (NC), and especially NC committed to the establishment of the sympatho-adrenal tissues. The NC is generated at the dorsal edge of the neural tube (NT) of the vertebrate embryo, under the action of NC specifier gene programs. NC cells (NCCs) undergo an epithelial to mesenchymal transition, and engage on a remarkable journey in the developing embryo, contributing to a plethora of cell-types and tissues. Various NCC sub-populations and derived lineages adopt specific migratory behaviors, moving individually as well as collectively, exploiting the different embryonic substrates they encounter along their path. Here we discuss how the specific features of NCC in development are re-iterated during NB metastatic behaviors.

FOXD3 may be a new cellular target biomarker as a hypermethylation gene in human ovarian cancer

Background

FOXD3 is aberrantly regulated in several tumors, but its underlying mechanisms in ovarian cancer (OC) remains largely unknown. The present study aimed to explore the role and associated mechanisms of FOXD3 in OC.

Methods

Microarray data from GEO was used to analyze differential CpG sites and differentially methylated regions (DMR) in tumor tissues and Illumina 450 genome-wide methylation data was employed. The FOXD3 expression level was determined through qRT-PCR and western blot analysis. Wound healing test, colony formation and flow cytometry assay were utilized to analyze cell migration, proliferation abilities, cell cycle and cell apoptosis, respectively. Finally, the effect of FOXD3 on tumor growth was investigated through in vivo xenograft experiments.

Results

GEO data analysis showed that FOXD3 was hypermethylated in OC tissues. Also, qRT-PCR revealed that FOXD3 was low expressed and methylation-specific PCR (MSP) confirmed that the methylation level of FOXD3 was hypermethylated. Combined treatment of 5-aza-2′-deoxycytidine (5-Aza-dC) could synergistically restored FOXD3 expression. Finally, in vitro and in vivo experiments showed that demethylated FOXD3 decreased cell proliferation and migration abilities, and increased the cell apoptosis. In vivo experiment detected that demethylated FOXD3 restrained tumor growth.

Conclusions

FOXD3 could act as a tumor suppressor to inhibit cell proliferation, migration and promote cell apoptosis in OC cells.

Electronic supplementary material

The online version of this article (10.1186/s12935-019-0755-8) contains supplementary material, which is available to authorized users.

Serum Fork-Head Box D3 (FOXD3) Expression Is Down-Regulated in and Associated with Diagnosis of Patients with Non-Small Cell Lung Cancer

Background

The aim of this study was to detect the expression of fork-head box D3 (FOXD3) and investigate its diagnostic value in patients with non-small cell lung cancer (NSCLC).

Material/Methods

The relative expression of FOXD3 at mRNA and protein levels was determined by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blotting analysis, respectively. Chi-square test was used to explore the relevance of FOXD3 expression with clinical features of NSCLC patients. A receiver operating characteristic (ROC) curve was built to estimate the diagnostic value of FOXD3 in distinguishing NSCLC patients from healthy controls.

Results

Serum FOXD3 expression was weakly expressed in NSCLC patients compared to the controls at mRNA and protein levels (P<0.001) and low FOXD3 expression was positively correlated with TNM stage, lymph node metastasis, and differentiation. The ROC curve indicated that FOXD3 acts as a diagnostic bio-marker for NSCLC patients, with an AUC of 0.826 corresponding to a sensitivity of 77.1% and a specificity of 74.6%, and an optimal cutoff point of 2.38.

Conclusions

Decreased expression of serum FOXD3 was observed in NSCLC patients, and it was found to be a potential molecular marker for the diagnosis of NSCLC.

MORC2 promotes development of an aggressive colorectal cancer phenotype through inhibition of NDRG1

MORC2 (microrchidia family CW‐type zinc finger 2) is a newly identified chromatin remodeling protein that functions in diverse biological processes including gene transcription. NDRG1 is a metastasis suppressor and a prognostic biomarker for colorectal cancer (CRC). However, the relationship between MORC2 and NDRG1 transcriptional regulation and the roles of MORC2 in CRC remain elusive. Here, we showed that MORC2 downregulated NDRG1 mRNA, protein levels, and promoter activity in CRC cells. We also found that MORC2 bound to the −446 to −213 bp region of the NDRG1 promoter. Mechanistically, histone deacetylase sirtuin 1 (SIRT1) was involved in NDRG1 transcriptional regulation. MORC2 was able to interact with SIRT1 and inhibit NDRG1 promoter activity cumulatively with SIRT1. MORC2 overexpression led to a decrease of H3Ac and H4Ac of the NDRG1 promoter. Importantly, we showed that NDRG1 was essential in MORC2‐mediated promotion of CRC cell migration and invasion in vitro, as well as lung metastasis of CRC cells in vivo. Moreover, MORC2 expression correlated negatively with NDRG1 expression in CRC patients. High expression of MORC2 was significantly associated with lymph node metastasis (P = 0.019) and poor pTNM stage (P = 0.02) and the expression of MORC2 correlated with poor prognosis in colon cancer patients. Our findings thus contribute to the knowledge of the regulatory mechanism of MORC2 in downregulating NDRG1, and suggest MORC2 as a potential therapeutic target for CRC.

The Dominant Role of Forkhead Box Proteins in Cancer

Forkhead box (FOX) proteins are multifaceted transcription factors that are significantly implicated in cancer, with various critical roles in biological processes. Herein, we provide an overview of several key members of the FOXA, FOXC, FOXM1, FOXO and FOXP subfamilies. Important pathophysiological processes of FOX transcription factors at multiple levels in a context-dependent manner are discussed. We also specifically summarize some major aspects of FOX transcription factors in association with cancer research such as drug resistance, tumor growth, genomic alterations or drivers of initiation. Finally, we suggest that targeting FOX proteins may be a potential therapeutic strategy to combat cancer.

Armadillo repeat containing 12 promotes neuroblastoma progression through interaction with retinoblastoma binding protein 4

Recent studies suggest the emerging roles of armadillo (ARM) family proteins in tumor progression. However, the functions and underlying mechanisms of ARM members in tumorigenesis and aggressiveness of neuroblastoma (NB) remain to be determined. Herein, we identify armadillo repeat containing 12 (ARMC12) as an ARM member associated with NB progression. ARMC12 promotes the growth and aggressiveness of NB cell lines. Mechanistically, ARMC12 physically interacts with retinoblastoma binding protein 4 (RBBP4) to facilitate the formation and activity of polycomb repressive complex 2, resulting in transcriptional repression of tumor suppressive genes. Blocking the interaction between ARMC12 and RBBP4 by cell-penetrating inhibitory peptide activates the downstream gene expression and suppresses the tumorigenesis and aggressiveness of NB cells. Both ARMC12 and RBBP4 are upregulated in NB tissues, and are associated with unfavorable outcome of patients. These findings suggest the crucial roles of ARMC12 in tumor progression and a potential therapeutic approach for NB.

Armadillo (ARM) family proteins can act as oncogenes or tumor suppressors. Here, the authors show that a new ARM protein (ARMC12) is upregulated in neuroblastoma, binds the PRC2 component RBBP4, and inhibits transcription of tumor suppressive genes.

Ets-1 promoter-associated noncoding RNA regulates the NONO/ERG/Ets-1 axis to drive gastric cancer progression

Emerging studies have indicated the essential functions of long noncoding RNAs (lncRNAs) during cancer progression. However, whether lncRNAs contribute to the upregulation of v-ets erythroblastosis virus E26 oncogene homolog 1 (Ets-1), an established oncogenic protein facilitating tumor invasion and metastasis, in gastric cancer remains elusive. Herein, we identified Ets-1 promoter-associated noncoding RNA (pancEts-1) as a novel lncRNA associated with the gastric cancer progression via mining of publicly available datasets and rapid amplification of cDNA ends. RNA pull-down, RNA immunoprecipitation, in vitro binding, and RNA electrophoretic mobility shift assays indicated the binding of pancEts-1 to non-POU domain containing octamer binding (NONO) protein. Mechanistically, pancEts-1 facilitated the physical interaction between NONO and Ets related gene (ERG), resulting in increased ERG transactivation and transcription of Ets-1 associated with gastric cancer progression. In addition, pancEts-1 facilitated the growth and aggressiveness of gastric cancer cells via interacting with NONO. In gastric cancer tissues, pancEts-1, NONO, and ERG were upregulated and significantly correlated with Ets-1 levels. High levels of pancEts-1, NONO, ERG, or Ets-1 were respectively associated with poor survival of gastric cancer patients, whereas simultaneous expression of all of them (HR = 3.012, P = 0.105) was not an independent prognostic factor for predicting clinical outcome. Overall, these results demonstrate that lncRNA pancEts-1 exhibits oncogenic properties that drive the progression of gastric cancer via regulating the NONO/ERG/Ets-1 axis.

HPSE enhancer RNA promotes cancer progression through driving chromatin looping and regulating hnRNPU/p300/EGR1/HPSE axis

Recent studies reveal the emerging functions of enhancer RNAs (eRNAs) in gene expression. However, the roles of eRNAs in regulating the expression of heparanase (HPSE), an established endo-β-D-glucuronidase essential for cancer invasion and metastasis, still remain elusive. Herein, through comprehensive analysis of publically available FANTOM5 expression atlas and chromatin interaction dataset, we identified a super enhancer and its derived eRNA facilitating the HPSE expression (HPSE eRNA) in cancers. Gain-of-function and loss-of-function experiments indicated that HPSE eRNA facilitated the in vitro and in vivo tumorigenesis and aggressiveness of cancer cells. Mechanistically, as a p300-regulated nuclear noncoding RNA, HPSE eRNA bond to heterogeneous nuclear ribonucleoprotein U (hnRNPU) to facilitate its interaction with p300 and their enrichment on super enhancer, resulting in chromatin looping between super enhancer and HPSE promoter, p300-mediated transactivation of transcription factor early growth response 1 (EGR1), and subsequent elevation of HPSE expression. In addition, rescue studies in HPSE overexpressing or silencing cancer cells indicated that HPSE eRNA exerted oncogenic properties via driving HPSE expression. In clinical cancer tissues, HPSE eRNA was highly expressed and positively correlated with HPSE levels, and served as an independent prognostic factor for poor outcome of cancer patients. Therefore, these findings indicate that as a novel noncoding RNA, HPSE eRNA promotes cancer progression through driving chromatin looping and regulating hnRNPU/p300/EGR1/HPSE axis.

FOXD3 regulates anaplastic thyroid cancer progression

Anaplastic thyroid cancer (ATC) is an aggressive malignancy with poor prognosis. It was reported that Forkhead box D3 (FOXD3) transcription factor is associated with several cancers. We investigated its antitumorigenic role of ATC in this study. The ATC cell lines SW1736 and K18 exhibited lower FOXD3 expression than the Nthy-ori-3-1 normal thyroid cell line. FOXD3 downregulation in ATC cell lines promoted invasiveness and epithelial-to-mesenchymal transition (EMT) and decreased cellular apoptosis. FOXD3 silencing also enhanced p-ERK levels in the ATC cell lines, suggesting it negatively regulated MAPK/ERK signaling. Silencing FOXD3 in SW1736 cells also led to generation of larger xenograft tumors with high p-ERK and low E-cadherin levels. Moreover, human ATC samples showed lower FOXD3 and higher p-ERK levels than samples of normal thyroid tissue. These findings demonstrate that FOXD3 acts as a tumor suppressor during anaplastic thyroid carcinogenesis and highlight its potential for clinical application.

Screening of FOXD3 targets in lung cancer via bioinformatics analysis

The purpose of the present study was to explore the targets of forkhead box D3 (FOXD3) in lung cancer, and thus contribute to the diagnosis and therapy of the disease. The gene expression profile of GSE64513 was downloaded from the Gene Expression Omnibus database. The dataset contained 3 FOXD3 knockout A549 lung cancer cell samples and 3 normal A549 cell samples. The differentially expressed genes (DEGs) between the FOXD3-knockout and normal A549 cells were identified using the limma package in R. The alternative splicing genes (ASGs) in FOXD3-knockout samples were identified by Replicate Multivariate Analysis of Transcript Splicing software. The Database for Annotation, Visualization and Integrated Discovery was used to identify the enriched functions and pathways of DEGs and ASGs. A protein-protein interaction (PPI) network was constructed based on results from the Search Tool for the Retrieval of Interacting Genes database and visualized using Cytoscape software. A total of 1,853 DEGs and 2,249 ASGs were identified in FOXD3-knockout A549 cells compared with normal A549 cells. The DEGs were enriched in 338 Gene Ontology (GO) terms and 21 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, and the ASGs were enriched in 470 GO terms and 22 KEGG pathways. A total of 199 overlaps between the DEGs and the ASGs were identified; a PPI network constructed based on the overlapping genes contained 97 nodes and 115 pairs. FOXD3 may serve an important role in regulating the growth, migration and proliferation of tumor cells in lung cancer. The present study indicates that a number of genes, including AURKA and NOS3, may be targets of FOXD3, mediating its effect in lung cancer.

miRNA-337-3p inhibits gastric cancer progression through repressing myeloid zinc finger 1-facilitated expression of matrix metalloproteinase 14

Matrix metalloproteinase 14 (MMP-14), a membrane-anchored MMP that promotes the tumorigenesis and aggressiveness, is highly expressed in gastric cancer. However, the transcriptional regulators of MMP-14 expression in gastric cancer still remain largely unknown. In this study, through mining computational algorithm programs and chromatin immunoprecipitation datasets, we identified adjacent binding sites of myeloid zinc finger 1 (MZF1) and miRNA-337-3p (miR-337-3p) within the MMP-14 promoter. We demonstrated that MZF1 directly bound to the MMP-14 promoter to facilitate its nascent transcription and expression in gastric cancer cell lines. In contrast, endogenous miR-337-3p suppressed the MMP-14 expression through recognizing its binding site within MMP-14 promoter. Mechanistically, miR-337-3p repressed the binding of MZF1 to MMP-14 promoter via recruiting Argonaute 2 and inducing repressive chromatin remodeling. Gain- and loss-of-function studies demonstrated that miR-337-3p suppressed the growth, invasion, metastasis, and angiogenesis of gastric cancer cells in vitro and in vivo through repressing MZF1-facilitated MMP-14 expression. In clinical specimens and cell lines of gastric cancer, MZF1 was highly expressed and positively correlated with MMP-14 expression. Meanwhile, miR-337-3p was under-expressed and inversely correlated with MMP-14 levels. miR-337-3p was an independent prognostic factor for favorable outcome of gastric cancer, and patients with high MZF1 or MMP-14 expression had lower survival probability. Taken together, these data indicate that miR-337-3p directly binds to the MMP-14 promoter to repress MZF1-facilitatd MMP-14 expression, thus suppressing the progression of gastric cancer.

microRNA-558 facilitates the expression of hypoxia-inducible factor 2 alpha through binding to 5'-untranslated region in neuroblastoma

Neuroblastoma (NB) is the most common extracranial solid tumor in childhood. Our previous studies have shown that hypoxia-inducible factor 2 alpha (HIF-2α), one member of the bHLH-PAS transcription factor family, facilitates the progression of NB under non-hypoxic conditions. However, the mechanisms underlying HIF-2α expression in NB still remain largely unknown. Herein, through analyzing the computational algorithm programs, we identified microRNA-558 (miR-558) as a crucial regulator of HIF-2α expression in NB. We demonstrated that miR-558 promoted the expression of HIF-2α at translational levels in NB cells through recruiting Argonaute 2 (AGO2). Mechanistically, miR-558 directly bound with its complementary site within 5′-untranslated region (5′-UTR) to facilitate the binding of AGO2 to eukaryotic translation initiation factor 4E (eIF4E) binding protein 1, resulting in increased eIF4E enrichment and HIF-2α translation. In addition, miR-558 promoted the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo, and these biological features were rescued by knockdown of AGO2, eIF4E, or HIF-2α. In clinical NB specimens, miR-558, AGO2, and eIF4E were highly expressed and positively correlated with HIF-2α expression. Patients with high miR-558, HIF-2α, AGO2, or eIF4E levels had lower survival probability. Taken together, these results demonstrate that miR-558 facilitates the expression of HIF-2α through bindingto its 5′-UTR, thus promoting the tumorigenesis and aggressiveness of NB.

TES inhibits colorectal cancer progression through activation of p38

The human TESTIN (TES) gene has been identified as a candidate tumor suppressor based on its location at a common fragile site – a region where loss of heterozygosity has been detected in numerous types of tumors. To investigate its role in colorectal cancer (CRC), we examined TES protein levels in CRC tissue samples and cell lines. We observed that TES was markedly reduced in both CRC tissue and cell lines. Additionally, overexpression of TES significantly inhibited cell proliferation, migration, and invasion, while increasing cell apoptosis in colon cancer cells. By contrast, shRNA-mediated TES knockdown elicited the opposite effects. TES inhibited the progression of CRC by up-regulating pro-apoptotic proteins, down-regulating anti-apoptotic proteins, and simultaneously activating p38 mitogen-activated protein kinase (MAPK) signaling pathways. Collectively, these data indicate that TES functions as a necessary suppressor of CRC progression by activating p38-MAPK signaling pathways. This suggests that TES may have a potential application in CRC diagnosis and targeted gene therapy.

FOXO4 and FOXD3 are predictive of prognosis in gastric carcinoma patients

Forkhead box (FOX) transcription factor family plays an important role in cancer growth and metastasis. This study aimed to determine the predictive ability of FOX genes in gastric carcinoma. A total of 360 patients with gastric from The Cancer Genome Atlas (TCGA) cohorts were collected in this study. The expression profile of FOX family were obtained from the TCGA RNAseq database. Clinicopathological characteristics, including age, gender, tumor node metastasis (TNM), tumor grade, and overall survival were collected. Univariate and multivariate Cox proportional hazards model were used to assess the risk factors for survival, and the results were further validated in in-house cohort. In the TCGA cohort, FOXO4 (HR = 0.613, 95%CI 0.452–0.832) and FOXD3 (HR = 1.704, 95%CI 1.212–2.397) were shown independently predictive of overall survival in gastric cancer after Cox proportional hazards analysis. The finding was validated in our in-house cohort, which demonstrated that both FOXO4 and FOXD3 were independent predictors for overall survival (FOXO4 high, HR: 0.445, 95%CI 0.277–0.715, P = 0.001, FOXD3 high, HR: 1.927, 95%CI 1.212–3.063, P = 0.006) and disease free survival (FOXO4 high, HR: 0.628, 95%CI 0.420–0.935, P = 0.022, FOXD3 high, HR: 1.698, 95%CI 1.136–2.540, P = 0.010). Collectively, FOX family paly critical roles in gastric cancer, and FOXO4 and FOXD3 were identified as independent prognostic factors for survival outcomes of gastric cancer. Further functional study is needed to understand more about FOX family in gastric cancer.

Risk-Associated Long Noncoding RNA FOXD3-AS1 Inhibits Neuroblastoma Progression by Repressing PARP1-Mediated Activation of CTCF

Neuroblastoma (NB) is the most common extracranial tumor in childhood. Recent studies have implicated the emerging roles of long noncoding RNAs (lncRNAs) in tumorigenesis and aggressiveness. However, the functions and targets of risk-associated lncRNAs in NB progression still remain to be determined. Herein, through mining of public microarray datasets, we identify lncRNA forkhead box D3 antisense RNA 1 (FOXD3-AS1) as an independent prognostic marker for favorable outcome of NB patients. FOXD3-AS1 is downregulated in NB tissues and cell lines, and ectopic expression of FOXD3-AS1 induces neuronal differentiation and decreases the aggressiveness of NB cells in vitro and in vivo. Mechanistically, as a nuclear lncRNA, FOXD3-AS1 interacts with poly(ADP-ribose) polymerase 1 (PARP1) to inhibit the poly(ADP-ribosyl)ation and activation of CCCTC-binding factor (CTCF), resulting in derepressed expression of downstream tumor-suppressive genes. Rescue experiments indicate that FOXD3-AS1 harbors tumor-suppressive properties by inhibiting the oncogenic roles of PARP1 or CTCF and plays crucial roles in all-trans-retinoic-acid-mediated therapeutic effects on NB. Administration of FOXD3-AS1 construct or siRNAs against PARP1 or CTCF reduces the tumor growth and prolongs the survival of nude mice. These findings suggest that as a risk-associated lncRNA, FOXD3-AS1 inhibits the progression of NB through repressing PARP1-mediated CTCF activation.

Neuroblastoma pathogenesis: deregulation of embryonic neural crest development

Neuroblastoma (NB) is an aggressive pediatric cancer that originates from neural crest tissues of the sympathetic nervous system. NB is highly heterogeneous both from a clinical and a molecular perspective. Clinically, this cancer represents a wide range of phenotypes ranging from spontaneous regression of 4S disease to unremitting treatment-refractory progression and death of high-risk metastatic disease. At a cellular level, the heterogeneous behavior of NB likely arises from an arrest and deregulation of normal neural crest development. In the present review, we summarize our current knowledge of neural crest development as it relates to pathways promoting 'stemness' and how deregulation may contribute to the development of tumor-initiating CSCs. There is an emerging consensus that such tumor subpopulations contribute to the evolution of drug resistance, metastasis and relapse in other equally aggressive malignancies. As relapsed, refractory disease remains the primary cause of death for neuroblastoma, the identification and targeting of CSCs or other primary drivers of tumor progression remains a critical, clinically significant goal for neuroblastoma. We will critically review recent and past evidence in the literature supporting the concept of CSCs as drivers of neuroblastoma pathogenesis.

TAT-mediated si-hWAPL inhibits the invasion and metastasis of cervical cancer stem cells

Human wings apart-like (hWAPL) is reported to have an association with cervical cancer. In the present study, the role of hWAPL in cervical cancer stem cells (CCSCs) was evaluated. Cervical tumorspheres were generated from cervical cancer tissues cultured in stem cell medium, and the expression of hWAPL by the tumorspheres was detected using immunohistochemistry. hWAPL expression levels in the tumorspheres were then upregulated using hWAPL adenoviral vectors or downregulated via the TAT-mediated knockdown of hWAPL and the effects on the tumorspheres were evaluated using colony formation, cell invasion and western blotting assays. The results demonstrated that the expression of hWAPL and human papillomavirus (HPV) was associated with the pluripotency of CCSCs, with hWAPL expression decreasing following the differentiation of cervical tumorspheres. Knockdown of hWAPL expression decreased HPV E6 expression and inhibited tumor invasion and colony formation. TAT-mediated knockdown of hWAPL with short interfering RNA significantly reduced tumor growth in nude mice. These results suggest that hWAPL is a marker of CCSC proliferation and is potentially a therapeutic target for cervical carcinoma through the downregulation of HPV E6.

miRNA-584-3p inhibits gastric cancer progression by repressing Yin Yang 1- facilitated MMP-14 expression

Recent evidence shows the emerging roles of promoter-targeting endogenous microRNAs (miRNAs) in regulating gene transcription. However, miRNAs affecting the transcription of matrix metalloproteinase 14 (MMP-14) in gastric cancer remain unknown. Herein, through integrative mining of public datasets, we identified the adjacent targeting sites of Yin Yang 1 (YY1) and miRNA-584-3p (miR-584-3p) within MMP-14 promoter. We demonstrated that YY1 directly targeted the MMP-14 promoter to facilitate its expression in gastric cancer cells. In contrast, miR-584-3p recognized its complementary site within MMP-14 promoter to suppress its expression. Mechanistically, miR-584-3p interacted with Argonaute 2 to recruit enhancer of zeste homolog 2 and euchromatic histone lysine methyltransferase 2, resulting in enrichment of repressive epigenetic markers and decreased binding of YY1 to MMP-14 promoter. miR-584-3p inhibited the in vitro and in vivo tumorigenesis and aggressiveness of gastric cancer cells through repressing YY1-facilitated MMP-14 expression. In clinical gastric cancer tissues, the expression of YY1 and miR-584-3p was positively or negatively correlated with MMP-14 levels. In addition, miR-584-3p and YY1 were independent prognostic factors associated with favorable and unfavorable outcome of gastric cancer patients, respectively. These data demonstrate that miR-584-3p directly targets the MMP-14 promoter to repress YY1-facilitated MMP-14 expression and inhibits the progression of gastric cancer.

Members of FOX family could be drug targets of cancers

FOX families play important roles in biological processes, including metabolism, development, differentiation, proliferation, apoptosis, migration, invasion and longevity. Here we are focusing on roles of FOX members in cancers, FOX members and drug resistance, FOX members and stem cells. Finally, FOX members as drug targets of cancer treatment were discussed. Future perspectives of FOXC1 research were described in the end.

MicroRNA-145 inhibits tumorigenesis and invasion of cervical cancer stem cells

MicroRNA (miR)-145 has been reported to induce cancer stem cell (CSC) differentiation through down-regulation of the stem cell transcription factors (TFs) that maintain CSC pluripotency. High expression of miR-145 indicates a good prognosis in cancer patients, but its role in cervical cancer stem cells (CCSCs) is not known. We show that expression of miR-145 and core stem cell transcription factors, Sox2, Nanog and Oct4, are associated with the pluripotency of CCSCs, with increased expression of miR-145 after cervical tumorsphere (CT) differentiation. miR-145 overexpression inhibited expression of core TFs, as well as decreasing tumor invasion and colony formation, whereas miR-145 knockdown led to the opposite effects. Injection of adenovirus-miR-145 significantly reduced tumor growth in nude mice. High miR-145 expression predicted a better prognosis compared with that in patients with low miR-145 expression after analyses of The Cancer Genome Atlas (TCGA) data. These results suggest that miR-145 is able to induce CT differentiation through enzymolyzing TFs and might be a therapeutic target for cervical carcinoma.

FOXD3 is a tumor suppressor of colon cancer by inhibiting EGFR-Ras-Raf-MEK-ERK signal pathway

Forkhead box D3 (FOXD3), as a transcriptional repressor, is well known to be involved in the regulation of development. Although FoxD3 is associated with several cancers, its role in colon cancer and the underlying mechanism are still unclear. Here, we first showed that FOXD3 knockdown dramatically increased the proliferation of human colon cancer cells, enhanced cell invasive ability and inhibited cell apoptosis. In vivo xenograft studies confirmed that the FOXD3-knockdown cells were more tumorigenic than the controls. Silencing FOXD3 markedly activated EGFR/Ras/Raf/MEK/ERK pathway in human colon cancer cells. In addition, blocking EGFR effectively decreased the activity of MAPK induced by FOXD3 knockdown. In human cancer tissue, the expression of FOXD3 was reduced, however, the EGFR/Ras/Raf/MEK/ERK pathway was activated. Our study indicates that FOXD3 may play a protective role in human colon formation by regulating EGFR/Ras/Raf/MEK/ERK signal pathway. It is proposed that FOXD3 may have potential as a new therapeutic target in human colon cancer treatment.

The FOXD3/miR-214/MED19 axis suppresses tumour growth and metastasis in human colorectal cancer

Background:

MiR-214 is aberrantly regulated in several tumours, but its underlying mechanisms in colorectal cancer (CRC) metastasis remain largely unknown. This study aimed to demonstrate the function and potential mechanism of miR-214 in regulating invasion and metastasis of CRC.

Methods:

The transcription factor and targets of miR-214 were predicted by bioinformatics and validated using ChIP and dual-luciferase reporter assay. DNA methylation status was explored using bisulphite sequencing PCR. The in vitro and in vivo function of miR-214 in CRC was evaluated using MTT, plate colony formation, Matrigel invasion and animal models. Real-time PCR or western blotting was performed to detect FOXD3, miR-214 and MED19 expressions in CRC cells and clinical specimens.

Results:

MiR-214 was downregulated in CRC and was significantly correlated with lymphatic metastasis. Downregulation of miR-214 might due to promoter hypermethylation in CRC. FOXD3 was validated as a transcription factor of miR-214 by ChIP assay. Dual-luciferase assay identified MED19 as a target of miR-214 in CRC. In vitro and in vivo experiments showed that miR-214 mediated the inhibiting effect of FOXD3 on proliferation, invasion and metastasis by targeting MED19. Spearman's correlation analysis showed a positive correlation between FOXD3 and miR-214, and negative correlations between FOXD3 and MED19, miR-214 and MED19 in CRC cells and clinical specimens.

Conclusions:

FOXD3/miR-214/MED19 axis is important for the regulation of growth, invasion and metastasis of CRC. Targeting the miR-214-mediated axis might be helpful for the treatment of CRC.

Down-regulation of miR-26b induces cisplatin resistance in nasopharyngeal carcinoma by repressing JAG1

Therapy against nasopharyngeal carcinoma (NPC) is hurdled by chemoresistance. Recent studies found that microRNA (miRNA) are important regulators of cancer resistance. In this study, we aimed to explore the role and mechanism of miR‐26b in regulating NPC cisplatin (CDDP) resistance. Real‐time PCR was used to evaluate miR‐26b levels in CDDP‐resistant and CDDP‐sensitive NPC cells, as well as human NPC tissues. MiR‐26b was ectopically overexpressed in CDDP‐resistant cells, followed by monitoring changes in cell viability and apoptosis. Interaction between JAG1 and miR‐26b was characterized by dual‐luciferase reporter assay. Furthermore, we investigated whether ectopic JAG1 expression reversed CDDP sensitivity induced by miR‐26b overexpression. The effect of FOXD3 down‐regulation on miR‐26b was also evaluated. Our results indicate that miR‐26b was lower in the CDDP‐resistant NPC cells, human NPC tissue, particularly in secondary metastases. Ectopic expression of miR‐26b sensitized NPC cells to CDDP. JAG1 is a target of miR‐26b, and its expression is inversely correlated with miR‐26b. Overexpression of JAG1 reversed the CDDP sensitivity induced by miR‐26b overexpression. FOXD3 expression was also down‐regulated in CDDP‐resistant NPC. FOXD3 promoted miR‐26b expression and down‐regulation of FOXD3 suppressed miR‐26b expression. Down‐regulation of miR‐26b is closely correlated with the CDDP resistance in NPC.

Down-regulation of long non-coding RNA FOXD3 antisense RNA 1 (FOXD3-AS1) inhibits cell proliferation, migration, and invasion in malignant glioma cells

Growing evidence indicates that long non-coding RNAs (lncRNAs) play key roles in cancer initiation and progression. However, little is known about the therapeutic significance of lncRNAs in glioma. In this study, we explored the tumorigenic role of a classical lncRNA, FOXD3 antisense RNA 1 (FOXD3-AS1) in glioma. Systemic analysis of the patient specimens and clinical data showed that FOXD3-AS1 was markedly up-regulated in high-grade glioma tissues (WHO grade III-IV) compared with that in low-grade glioma (WHO grade I-II) and normal brain tissues (both P<0.01), and patients with low FOXD3-AS1 expression had grater survival probability. Multivariate regression analysis showed that increased FOXD3-AS1 expression was a significant independent indicator of poor prognosis in glioma patients (P=0.034). To understand the tumorigenic mechanism of FOXD3-AS1, the expression pattern and functional role of FOXD3-AS1 in glioma were detected using real-time PCR and Smart Silencer-mediated knockdown study. In related cell biological assays, we discovered that FOXD3-AS1 knockdown significantly inhibited cell proliferation, induced cell cycle S-phase arrest, and impaired cell migration and invasion in malignant glioma cells. As expected, we also found that the expression of FOXD3-AS1 was positively correlated with FOXD3 mRNA. Knockdown of FOXD3-AS1 reduced the protein level of FOXD3 in cultured U251 and A172 cell lines. These results suggest that FOXD3-AS1 is an oncogenic lncRNA, which may promote the occurrence and development of glioma through transcriptional regulation of FOXD3.

miRNA-337-3p suppresses neuroblastoma progression by repressing the transcription of matrix metalloproteinase 14

Recent evidence shows the emerging roles of endogenous microRNAs (miRNAs) in repressing gene transcription. However, the miRNAs inhibiting the transcription of matrix metalloproteinase 14 (MMP-14), a membrane-anchored MMP crucial for the tumorigenesis and aggressiveness, still remain largely unknown. In this study, through mining computational algorithm program and genome-wide Argonaute profiling dataset, we identified one binding site of miRNA-337-3p (miR-337-3p) within the MMP-14 promoter. We demonstrated that miR-337-3p was under-expressed and inversely correlated with MMP-14 expression in clinical specimens and cell lines of neuroblastoma (NB), the most common extracranial solid tumor in childhood. Patients with high miR-337-3p expression had greater survival probability. miR-337-3p suppressed the promoter activity, nascent transcription, and expression of MMP-14, resulting in decreased levels of vascular endothelial growth factor, in cultured NB cell lines. Mechanistically, miR-337-3p recognized its binding site and recruited Argonaute 2 to facilitate the enrichment of repressive epigenetic markers and decrease the binding of RNA polymerase II and specificity protein 1 on the MMP-14 promoter. Gain- and loss-of-function studies demonstrated that miR-337-3p suppressed the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo. In addition, restoration of MMP-14 expression rescued the NB cells from changes in these biological features. Taken together, these data indicate that miR-337-3p directly binds the MMP-14 promoter to repress its transcription, thus suppressing the progression of NB.

Smad4 suppresses the tumorigenesis and aggressiveness of neuroblastoma through repressing the expression of heparanase

Heparanase (HPSE) is the only endo-β-D-glucuronidase that is correlated with the progression of neuroblastoma (NB), the most common extracranial malignancy in childhood. However, the mechanisms underlying HPSE expression in NB still remain largely unknown. Herein, through analyzing cis-regulatory elements and mining public microarray datasets, we identified SMAD family member 4 (Smad4) as a crucial transcription regulator of HPSE in NB. We demonstrated that Smad4 repressed the HPSE expression at the transcriptional levels in NB cells. Mechanistically, Smad4 suppressed the HPSE expression through directly binding to its promoter and repressing the lymphoid enhancer binding factor 1 (LEF1)-facilitated transcription of HPSE via physical interaction. Gain- and loss-of-function studies demonstrated that Smad4 inhibited the growth, invasion, metastasis, and angiogenesis of NB cells in vitro and in vivo. Restoration of HPSE expression prevented the NB cells from changes in these biological features induced by Smad4. In clinical NB specimens, Smad4 was under-expressed and inversely correlated with HPSE levels, while LEF1 was highly expressed and positively correlated with HPSE expression. Patients with high Smad4 expression, low LEF1 or HPSE levels had greater survival probability. These results demonstrate that Smad4 suppresses the tumorigenesis and aggressiveness of NB through repressing the HPSE expression.

Knockdown of FOXK1 alone or in combination with apoptosis-inducing 5-FU inhibits cell growth in colorectal cancer

Forkhead box K1 (FOXK1) is a member of the FOX transcription factor family, which plays an important role in oncogenesis. However, the exact function and mechanism of FOXK1 in human colorectal cancers (CRCs) remain unclear. In the present study, we first screened for potential FOXK1 target genes by ectopically expressing FOXK1 in SW480 cells and examined the subsequent changes in the expression levels of major oncogenes using RT-PCR. We also evaluated the effects of FOXK1 regulation on growth and apoptosis. In addition, we investigated the biological impact of FOXK1 knockdown on CRC cells in vitro and in vivo. We found that FOXK1 overexpression increased the expression of multiple oncogenes in vitro. FOXK1 promoted serum-dependent and anchorage-dependent and -independent cell growth. Knockdown of FOXK1 induced G0/G1 cell cycle arrest in CRC cells. Moreover, FOXK1 suppression induced apoptosis and increased cell susceptibility to 5-fluorouracil (5-FU)-induced apoptosis. Furthermore, a xenograft model was established to explore FOXK1 shRNA-mediated tumorigenesis in vivo. A strong antitumorigenic effect of FOXK1-shRNA was enhanced when combined with 5-FU treatment. These findings implicate FOXK1 as a cell cycle and growth modulator that inhibits apoptosis in colon cancer cells. FOXK1-shRNA may serve as a novel and potent therapeutic agent, alone or with 5-FU, against colon cancer.

NUDT2 Disruption Elevates Diadenosine Tetraphosphate (Ap4A) and Down-Regulates Immune Response and Cancer Promotion Genes

Regulation of gene expression is one of several roles proposed for the stress-induced nucleotide diadenosine tetraphosphate (Ap₄A). We have examined this directly by a comparative RNA-Seq analysis of KBM-7 chronic myelogenous leukemia cells and KBM-7 cells in which the NUDT2 Ap₄A hydrolase gene had been disrupted (NuKO cells), causing a 175-fold increase in intracellular Ap₄A. 6,288 differentially expressed genes were identified with P < 0.05. Of these, 980 were up-regulated and 705 down-regulated in NuKO cells with a fold-change ≥ 2. Ingenuity^® Pathway Analysis (IPA^®) was used to assign these genes to known canonical pathways and functional networks. Pathways associated with interferon responses, pattern recognition receptors and inflammation scored highly in the down-regulated set of genes while functions associated with MHC class II antigens were prominent among the up-regulated genes, which otherwise showed little organization into major functional gene sets. Tryptophan catabolism was also strongly down-regulated as were numerous genes known to be involved in tumor promotion in other systems, with roles in the epithelial-mesenchymal transition, proliferation, invasion and metastasis. Conversely, some pro-apoptotic genes were up-regulated. Major upstream factors predicted by IPA^® for gene down-regulation included NFκB, STAT1/2, IRF3/4 and SP1 but no major factors controlling gene up-regulation were identified. Potential mechanisms for gene regulation mediated by Ap₄A and/or NUDT2 disruption include binding of Ap₄A to the HINT1 co-repressor, autocrine activation of purinoceptors by Ap₄A, chromatin remodeling, effects of NUDT2 loss on transcript stability, and inhibition of ATP-dependent regulatory factors such as protein kinases by Ap₄A. Existing evidence favors the last of these as the most probable mechanism. Regardless, our results suggest that the NUDT2 protein could be a novel cancer chemotherapeutic target, with its inhibition potentially exerting strong anti-tumor effects via multiple pathways involving metastasis, invasion, immunosuppression and apoptosis.

Intelectin 1 suppresses tumor progression and is associated with improved survival in gastric cancer

Recent evidence shows the emerging roles of intelectin 1 (ITLN1), a secretory lectin, in human cancers. Our previous studies have implicated the potential roles of ITLN1 in the aggressiveness of gastric cancer. Herein, we investigated the functions, downstream targets, and clinical significance of ITLN1 in the progression of gastric cancer. We demonstrated that ITLN1 increased the levels of hepatocyte nuclear factor 4 alpha (HNF4α), resulting in suppression of nuclear translocation and transcriptional activity of β-catenin in gastric cancer cells. Mechanistically, ITLN1 attenuated the activity of nuclear factor-kappa B, a transcription factor repressing the HNF4α expression, in gastric cancer cells through inactivating the phosphoinositide 3-kinase/AKT/Ikappa B kinase signaling. Gain- and loss-of-function studies demonstrated that ITLN1 suppressed the growth, invasion, and metastasis of gastric cancer cells in vitro and in vivo. In addition, restoration of HNF4α expression prevented the gastric cancer cells from ITLN1-mediated changes in these biological features. In clinical gastric cancer tissues, HNF4α expression was positively correlated with that of ITLN1. Patients with high ITLN1 or HNF4α expression had greater survival probability. Taken together, these data indicate that ITLN1 suppresses the progression of gastric cancer through up-regulation of HNF4α, and is associated with improved survival in patients with gastric cancer.

The aspirin-induced long non-coding RNA OLA1P2 blocks phosphorylated STAT3 homodimer formation

Background

Although the chemopreventive effects of aspirin have been extensively investigated, the roles of many cell components, such as long non-coding RNAs, in these effects are still not completely understood.

Results

We identify an aspirin-induced upregulated lncRNA, OLA1P2, in human colorectal cancer. Aspirin induces demethylation of the FOXD3 promoter and promotes expression of the FOXD3 gene. Subsequently, upregulated FOXD3 protein transcriptionally activates lncRNA OLA1P2 expression. OLA1P2 upregulation markedly affects STAT3 signaling pathway activity by inhibiting the nuclear import of phosphorylated STAT3. The phosphorylation of tyrosine-705 of STAT3 is the first step in OLA1P2 binding, and the formation of phosphorylated STAT3 homodimers is subsequently blocked. OLA1P2 interacts directly with STAT3 due to OLA1P2 sharing the same conservative STAT3 transcription response element as STAT3 targets. Regular use of aspirin dramatically decreases the number of metastatic nodules of cancer cells in immunodeficient mouse lungs, and OLA1P2 silencing markedly weakens the anti-metastatic activity of aspirin in the lungs. Additionally, low OLA1P2 levels are associated with malignant transformation and lower overall survival in cancers.

Conclusions

The present study finds that the aspirin-FOXD3-OLA1P2-STAT3 axis exhibits exciting anticancer effects and provides new insights into the chemopreventive mechanisms underlying aspirin use.

Electronic supplementary material

The online version of this article (doi:10.1186/s13059-016-0892-5) contains supplementary material, which is available to authorized users.

FOXR2 contributes to cell proliferation and malignancy in human hepatocellular carcinoma

Forkhead box R2 (FOXR2), a member of forkhead box (FOX) family, has been identified as an oncogene in medulloblastoma and breast cancer recently. However, the expression and function of FOXR2 in hepatocellular carcinoma cell (HCC) are still unclear. Here, we report that FOXR2 is frequently upregulated in 25/42 (59.5 %) of HCC specimens compared with neighboring non-cancerous tissues in messenger RNA (mRNA) level and further confirmed by immunohistochemistry analysis in protein level. Cellular function analyses revealed that FOXR2 promoted cell growth and colony formation, whereas knockdown of FOXR2 by RNA inference inhibited cell growth and decreased the growth ability of HCC cells in soft agar. Moreover, we also found FOXR2 overexpression facilitated the development of tumor xenografts in nude mice model. In addition, we validated β-catenin, Skp2, c-Myc, and Gli-1 as the potential downstream effectors of FOXR2 in the regulation of cell proliferation and malignancy by quantitative real-time PCR analysis. Collectively, our data suggest that FOXR2 promotes cell proliferation and malignancy in HCC and could be a novel promising therapeutic target for this disease.

MicroRNA‑451 inhibits neuroblastoma proliferation, invasion and migration by targeting macrophage migration inhibitory factor

Neuroblastoma (NB) is the most prevalent type of extracranial solid tumour in young children. To improve current understanding of the mechanisms, which modulate cancer cell proliferation, invasion and migration, investigations have focused on microRNAs (miRs), a class of small non‑coding RNAs, which post‑transcriptionally regulate gene expression during various crucial cell processes. The present study aimed to investigate the role of miR‑451 in NB. Human NB tissue and adjacent normal tissue were surgically removed, and the expression of miR‑451, and development and pathological characteristics of NB were investigated. The expression of miR‑451 was reduced in the NB tissue, compared with that in the adjacent tissue, and correlations between the reduction in miR‑451 and unfavourable variables included tumour size (P=0.0081), differentiation (P=0.0217), lymph node metastasis (P=0.0489), tumour‑node‑metastasis stage (0.0220) and distant metastases (P=0.0201). Transfection of the SK‑N‑SH and GI‑LA‑N NB cell lines with miR‑451 inhibited cell growth, invasion and migration. Furthermore, the present study demonstrated that macrophage migration inhibitory factor (MIF) was regulated directly by miR‑451 and was a critical mediator of the biological effects of miR‑451 in NB. The re‑expression of MIF markedly reversed the carcinogenic inhibitory property of miR‑451. These data provide a more detailed understanding of the essential role of miR‑451 in NB, which relies on regulation of the expression of MIF.

In silico, in vitro and in vivo analysis identifies a potential role for steroid hormone regulation of FOXD3 in endometriosis-associated genes

STUDY QUESTION

Can bioinformatics analysis of publically available microarray datasets be utilized in identifying potentially important transcription factors (TF) in the hormonal regulation of the endometrium?

SUMMARY ANSWER

Systems integration and analysis of existing complex (published) datasets, predicted a role for the novel transcription factor, Forkhead Box D3 (FOXD3) in healthy endometrium and in endometriosis, which was followed by the demonstration of decreased levels of the protein upon decidualisation of normal human endometrial stromal cells in vitro and differential endometrial expression in the stroma in endometriosis.

WHAT IS KNOWN ALREADY

The reported endometriosis-associated endometrial aberrations are most pronounced in the progesterone-dominant secretory phase and progesterone resistance is a proposed causative factor.

STUDY DESIGN, SIZE, DURATION

The study was initially an 'in silico' study, with confirmatory 'wet lab' data from western blotting (WB), qPCR and Immunohistochemistry (IHC) on endometrial biopsies obtained from 142 women undergoing gynaecological surgery.

PARTICIPANTS/MATERIALS, SETTING, METHODS

The study was conducted at a University Research Institute. Bioinformatic analysis of selected published microarray datasets identified differentially regulated genes for the early and mid-secretory phases relative to the proliferative phase. Diseases and Functions categories were identified with Ingenuity (IPA) 'core analysis' software. The key transcription factors controlling secretory phase gene changes were revealed with oPOSSUM software. FOXD3 expression levels were examined in human endometrial samples from women aged 18-55 years by WB, IHC, and qPCR. The progesterone regulation of endometrial FOXD3 levels was examined in vivo and in cultured primary human endometrial stromal cells in vitro.

MAIN RESULTS AND THE ROLE OF CHANCE

Initial data mining and subsequent bioinformatics analysis of human endometrial microarray datasets identified FOXD3 to be a key regulator of gene expression specific to secretory phase/endometriosis. FOXD3 was dynamically expressed in healthy endometrium and differentially expressed in endometriosis. In vitro decidualisation of primary endometrial stromal cells significantly decreased FOXD3 protein (P = 0.0005) and progestagen (Levonorgestrel) treatment also reduced the high endometrial FOXD3 protein (P = 0.0001) and mRNA levels (P = 0.04) seen in untreated women with endometriosis, with a shift of FOXD3 from the nucleus to the cytoplasm.

LIMITATIONS, REASONS FOR CAUTION

The quality of Bioinformatics analysis and results depends on the published micro-array data.

WIDER IMPLICATIONS OF THE FINDINGS

An in depth analysis of FOXD3 function and its relationship with estrogen and progesterone might provide insights into its potential deregulation in proliferative disorders of the endometrium including endometrial cancer where its expression is also deregulated. Further, FOX transcription factors are increasingly seen as novel therapeutic targets in disease.

STUDY FUNDING/COMPETING INTERESTS

We acknowledge the support by Wellbeing of Women project grant RG1073 (D.K.H., A.J.V.). We also acknowledge the support of Liverpool Women's Hospital Foundation Trust (J.A.D.), Institute of Translational Medicine (D.M., A.J.V., D.K.H.) and the Institute of Integrative Biology (O.V.), University of Liverpool. All authors declare no conflict of interest.

TRIAL REGISTRATION NUMBER

N/A.

Mining for novel tumor suppressor genes using a shortest path approach

Cancer, being among the most serious diseases, causes many deaths every year. Many investigators have devoted themselves to designing effective treatments for this disease. Cancer always involves abnormal cell growth with the potential to invade or spread to other parts of the body. In contrast, tumor suppressor genes (TSGs) act as guardians to prevent a disordered cell cycle and genomic instability in normal cells. Studies on TSGs can assist in the design of effective treatments against cancer. In this study, we propose a computational method to discover potential TSGs. Based on the known TSGs, a number of candidate genes were selected by applying the shortest path approach in a weighted graph that was constructed using protein-protein interaction network. The analysis of selected genes shows that some of them are new TSGs recently reported in the literature, while others may be novel TSGs.

CTCF cooperates with noncoding RNA MYCNOS to promote neuroblastoma progression through facilitating MYCN expression

Previous studies have indicated the important roles of MYCN in tumorigenesis and progression of neuroblastoma (NB), the most common extracranial solid tumor derived from neural crest in childhood. However, the regulatory mechanisms of MYCN expression in NB still remain largely unknown. In this study, through mining public microarray databases and analyzing the cis-regulatory elements and chromatin immunoprecipitation data sets, we identified CCCTC-binding factor (CTCF) as a crucial transcription factor facilitating the MYCN expression in NB. RNA immunoprecipitation, RNA electrophoretic mobility shift assay, RNA pull down and in vitro binding assay indicated the physical interaction between CTCF and MYCN opposite strand (MYCNOS), a natural noncoding RNA surrounding the MYNC promoter. Gain- and loss-of-function studies revealed that MYCNOS facilitated the recruitment of CTCF to its binding sites within the MYCN promoter to induce chromatin remodeling, resulting in enhanced MYCN levels and altered downstream gene expression, in cultured NB cell lines. CTCF cooperated with MYCNOS to suppress the differentiation and promote the growth, invasion and metastasis of NB cells in vitro and in vivo. In clinical NB tissues and cell lines, CTCF and MYCNOS were upregulated and positively correlated with MYCN expression. CTCF was an independent prognostic factor for unfavorable outcome of NB, and patients with high MYCNOS expression had lower survival probability. Taken together, these results demonstrate that CTCF cooperates with noncoding RNA MYCNOS to exhibit oncogenic activity that affects the aggressiveness and progression of NB through transcriptional upregulation of MYCN.

FOXD3 suppresses tumor growth and angiogenesis in non-small cell lung cancer

The transcription factor forkhead box D3 (FOXD3), widely studied as a transcriptional repressor in embryogenesis, participates in the carcinogenesis of many cancers. However, the expression pattern and role of FOXD3 in non-small cell lung cancer (NSCLC) have not been well characterized. We report that FOXD3 is significantly downregulated in NSCLC cell lines and clinical tissues. FOXD3 overexpression significantly inhibits cell growth and results in G1 cell cycle arrest in NSCLC A549 and H1299 cells. In a xenograft tumor model, FOXD3 overexpression inhibits tumor growth and angiogenesis. Remarkably, expression of vascular endothelial growth factor (VEGF) was reduced in FOXD3 overexpression models both in vitro and in vivo. These findings suggest that FOXD3 plays a potential tumor suppressor role in NSCLC progression and represents a promising clinical prognostic marker and therapeutic target for this disease.