Nuclear Factor I/B: A Master Regulator of Cell Differentiation with Paradoxical Roles in Cancer

Genome-Wide Analysis Identifies Nuclear Factor 1C as a Novel Transcription Factor and Potential Therapeutic Target in SCLC

INTRODUCTION

Recent insights regarding mechanisms mediating stemness, heterogeneity, and metastatic potential of lung cancers have yet to be fully translated to effective regimens for the treatment of these malignancies. This study sought to identify novel targets for lung cancer therapy.

METHODS

Transcriptomes and DNA methylomes of 14 SCLC and 10 NSCLC lines were compared with normal human small airway epithelial cells (SAECs) and induced pluripotent stem cell (iPSC) clones derived from SAEC. SCLC lines, lung iPSC (Lu-iPSC), and SAEC were further evaluated by DNase I hypersensitive site sequencing (DHS-seq). Changes in chromatin accessibility and depths of transcription factor (TF) footprints were quantified using Bivariate analysis of Genomic Footprint. Standard techniques were used to evaluate growth, tumorigenicity, and changes in transcriptomes and glucose metabolism of SCLC cells after NFIC knockdown and to evaluate NFIC expression in SCLC cells after exposure to BET inhibitors.

RESULTS

Considerable commonality of transcriptomes and DNA methylomes was observed between Lu-iPSC and SCLC; however, this analysis was uninformative regarding pathways unique to lung cancer. Linking results of DHS-seq to RNA sequencing enabled identification of networks not previously associated with SCLC. When combined with footprint depth, NFIC, a transcription factor not previously associated with SCLC, had the highest score of occupancy at open chromatin sites. Knockdown of NFIC impaired glucose metabolism, decreased stemness, and inhibited growth of SCLC cells in vitro and in vivo. ChIP-seq analysis identified numerous sites occupied by BRD4 in the NFIC promoter region. Knockdown of BRD4 or treatment with Bromodomain and extra-terminal domain (BET) inhibitors (BETis) markedly reduced NFIC expression in SCLC cells and SCLC PDX models. Approximately 8% of genes down-regulated by BETi treatment were repressed by NFIC knockdown in SCLC, whereas 34% of genes repressed after NFIC knockdown were also down-regulated in SCLC cells after BETi treatment.

CONCLUSIONS

NFIC is a key TF and possible mediator of transcriptional regulation by BET family proteins in SCLC. Our findings highlight the potential of genome-wide chromatin accessibility analysis for elucidating mechanisms of pulmonary carcinogenesis and identifying novel targets for lung cancer therapy.

A comprehensive review on lncRNA LOXL1-AS1: molecular mechanistic pathways of lncRNA LOXL1-AS1 in tumorigenicity of cancer cells

Long non-coding RNAs (lncRNAs) are versatile RNAs that regulate various cellular processes, such as gene regulation, by acting as signals, decoys, guides, and scaffolds. A novel recognized lncRNA, LOXL1-antisense RNA 1 (LOXL1-AS1), is dysregulated in some diseases, including cancer, and acts as an oncogenic lncRNA in many types of cancer cells. Upregulation of LOXL1-AS1 has been involved in proliferation, migration, metastasis, and EMT, as well as inhibiting apoptosis in cancer cells. Most importantly, the malignant promoting activity of LOXL1-AS1 can be mostly mediated by sequestering specific miRNAs and inhibiting their binding to the 3´UTR of their target mRNAs, thereby indirectly regulating gene expression. Additionally, LOXL1-AS1 can decoy transcription factors and proteins and prevent their binding to their regulatory regions, inhibiting their mechanistic activity on the regulation of gene expression and signaling pathways. This review presents the mechanistic pathways of the oncogenic role of LOXL1-AS1 by modulating its target miRNAs and proteins in various cancer cells. Having information about the molecular mechanisms regulated by LOXL1-AS1 in cancer cells can open ways to find out particular prognostic biomarkers, as well as discover novel therapeutic approaches for different types of cancer.

Identification and bioinformatic characterization of a serum miRNA signature for early detection of laryngeal squamous cell carcinoma

BACKGROUND

The growing understanding of cancer biology and the establishment of new treatment modalities has not yielded the expected results in terms of survival for Laryngeal Squamous Cell Cancer (LSCC). Early diagnosis, as well as prompt identification of patients with high risk of relapse would ensure greater chance of therapeutic success. However, this goal remains a challenge due to the absence of specific biomarkers for this neoplasm.

METHODS

Serum samples from 45 LSCC patients and 23 healthy donors were collected for miRNA expression profiling by TaqMan Array analysis. Additional 20 patients and 42 healthy volunteers were included for the validation set, reaching an equal number of clinical samples for each group. The potential diagnostic ability of the such identified three-miRNA signature was confirmed by ROC analysis. Moreover, each miRNA was analyzed for the possible correlation with HNSCC patients' survival and TNM status by online databases Kaplan-Meier (KM) plotter and OncomiR. In silico analysis of common candidate targets and their network relevance to predict shared biological functions was finally performed by PANTHER and GeneMANIA software.

RESULTS

We characterized serum miRNA profile of LSCC patients identifying a novel molecular signature, including miR-223, miR-93 and miR-532, as circulating marker endowed with high selectivity and specificity. The oncogenic effect and the prognostic significance of each miRNA was investigated by bioinformatic analysis, denoting significant correlation with OS. To analyse the molecular basis underlying the pro-tumorigenic role of the signature, we focused on the simultaneously regulated gene targets-IL6ST, GTDC1, MAP1B, CPEB3, PRKACB, NFIB, PURB, ATP2B1, ZNF148, PSD3, TBC1D15, PURA, KLF12-found by prediction tools and deepened for their functional role by pathway enrichment analysis. The results showed the involvement of 7 different biological processes, among which inflammation, proliferation, migration, apoptosis and angiogenesis.

CONCLUSIONS

In conclusion, we have identified a possible miRNA signature for early LSCC diagnosis and we assumed that miR-93, miR-223 and miR-532 could orchestrate the regulation of multiple cancer-related processes. These findings encourage the possibility to deepen the molecular mechanisms underlying their oncogenic role, for the desirable development of novel therapeutic opportunities based on the use of short single-stranded oligonucleotides acting as non-coding RNA antagonists in cancer.

Establishment and characterization of cMYB-expressing human salivary adenoid cystic carcinoma cell lines (UM-HACC-14, UM-HACC-6) and matching patient-derived xenograft model (UM-PDX-HACC-14)

OBJECTIVE

Limited availability of authentic human adenoid cystic carcinoma (ACC) cell lines has hindered progress in understanding mechanisms underpinning the biology of this disease and the development of safe and effective therapies.

STUDY DESIGN

Surgical human ACC specimens (UM-HACC-6, UM-HACC-14) were dissociated into single cell suspensions and cultured in fibronectin-coated flasks. Alternatively, tumor fragments were transplanted subcutaneously into female immunodeficient (SCID) mice to establish patient-derived xenograft tumors (PDX; UM-PDX-HACC-14).

RESULTS

Both ACC cell lines showed continuous growth in monolayers for over 100 passages. Total RNA-Seq, RT-PCR, and FISH analysis revealed that both are MYB-NFIB fusion negative. Western blots revealed passage-dependent expression of E-Cadherin, PCNA, p63, phospho-c-MYB, and NFIB. Both, UM-HACC-14 and UM-HACC-6 cells exhibited tumorigenic potential when injected orthotopically into mouse submandibular glands.

CONCLUSION

UM-HACC-14, patient-matching UM-PDX-HACC-14, and the UM-HACC-6 cell line are new, authenticated preclinical models of ACC that are well suited for mechanistic and developmental therapeutics studies.

Cancer-specific epigenome identifies oncogenic hijacking by nuclear factor I family proteins for medulloblastoma progression

Normal cells coordinate proliferation and differentiation by precise tuning of gene expression based on the dynamic shifts of the epigenome throughout the developmental timeline. Although non-mutational epigenetic reprogramming is an emerging hallmark of cancer, the epigenomic shifts that occur during the transition from normal to malignant cells remain elusive. Here, we capture the epigenomic changes that occur during tumorigenesis in a prototypic embryonal brain tumor, medulloblastoma. By comparing the epigenomes of the different stages of transforming cells in mice, we identify nuclear factor I family of transcription factors, known to be cell fate determinants in development, as oncogenic regulators in the epigenomes of precancerous and cancerous cells. Furthermore, genetic and pharmacological inhibition of NFIB validated a crucial role of this transcription factor by disrupting the cancer epigenome in medulloblastoma. Thus, this study exemplifies how epigenomic changes contribute to tumorigenesis via non-mutational mechanisms involving developmental transcription factors.

Current diagnosis and treatment of salivary gland-type tumors of the lung

Salivary gland-type tumors of the lung are thought to originate from the submucosal exocrine glands of the large airways. Due to their rare occurrence, reports of their study are limited to small-scale or case reports. Therefore, daily clinical practices often require a search for previous reports. In the last 20 years, several genetic rearrangements have been identified, such as MYB::NF1B rearrangements in adenoid cystic carcinoma, CRTC1::MAML2 rearrangements in mucoepidermoid carcinoma, EWSR1::ATF1 rearrangements in hyalinizing clear cell carcinoma and rearrangements of the EWSR1 locus or FUS (TLS) locus in myoepithelioma and myoepithelial carcinoma. These molecular alterations have been useful in diagnosing these tumors, although they have not yet been linked to molecularly targeted therapies. The morphologic, immunophenotypic, and molecular characteristics of these tumors are similar to those of their counterparts of extrapulmonary origin, so clinical and radiologic differential diagnosis is required to distinguish between primary and metastatic disease of other primary sites. However, these molecular alterations can be useful in differentiating them from other primary lung cancer histologic types. The management of these tumors requires broad knowledge of the latest diagnostics, surgery, radiotherapy, bronchoscopic interventions, chemotherapy, immunotherapy as well as therapeutic agents in development, including molecularly targeted agents. This review provides a comprehensive overview of the current diagnosis and treatment of pulmonary salivary gland tumors, with a focus on adenoid cystic carcinoma and mucoepidermoid carcinoma, which are the two most common subtypes.

MiR-326-mediated overexpression of NFIB offsets TGF-β induced epithelial to mesenchymal transition and reverses lung fibrosis

Idiopathic Pulmonary Fibrosis (IPF) is a progressively fatal and incurable disease characterized by the loss of alveolar structures, increased epithelial-mesenchymal transition (EMT), and aberrant tissue repair. In this study, we investigated the role of Nuclear Factor I-B (NFIB), a transcription factor critical for lung development and maturation, in IPF. Using both human lung tissue samples from patients with IPF, and a mouse model of lung fibrosis induced by bleomycin, we showed that there was a significant reduction of NFIB both in the lungs of patients and mice with IPF. Furthermore, our in vitro experiments using cultured human lung cells demonstrated that the loss of NFIB was associated with the induction of EMT by transforming growth factor beta (TGF-β). Knockdown of NFIB promoted EMT, while overexpression of NFIB suppressed EMT and attenuated the severity of bleomycin-induced lung fibrosis in mice. Mechanistically, we identified post-translational regulation of NFIB by miR-326, a miRNA with anti-fibrotic effects that is diminished in IPF. Specifically, we showed that miR-326 stabilized and increased the expression of NFIB through its 3'UTR target sites for Human antigen R (HuR). Moreover, treatment of mice with either NFIB plasmid or miR-326 reversed airway collagen deposition and fibrosis. In conclusion, our study emphasizes the critical role of NFIB in lung development and maturation, and its reduction in IPF leading to EMT and loss of alveolar structures. Our study highlights the potential of miR-326 as a therapeutic intervention for IPF. The schema shows the role of NFIB in maintaining the normal epithelial cell characteristics in the lungs and how its reduction leads to a shift towards mesenchymal cell-like features and pulmonary fibrosis. A In normal lungs, NFIB is expressed abundantly in the epithelial cells, which helps in maintaining their shape, cell polarity and adhesion molecules. However, when the lungs are exposed to factors that induce pulmonary fibrosis, such as bleomycin, or TGF-β, the epithelial cells undergo epithelial to mesenchymal transition (EMT), which leads to a decrease in NFIB. B The mesenchymal cells that arise from EMT appear as spindle-shaped with loss of cell junctions, increased cell migration, loss of polarity and expression of markers associated with mesenchymal cells/fibroblasts. C We designed a therapeutic approach that involves exogenous administration of NFIB in the form of overexpression plasmid or microRNA-326. This therapeutic approach decreases the mesenchymal cell phenotype and restores the epithelial cell phenotype, thus preventing the development or progression of pulmonary fibrosis.

Epigenetic reprogramming of a distal developmental enhancer cluster drives SOX2 overexpression in breast and lung adenocarcinoma

Enhancer reprogramming has been proposed as a key source of transcriptional dysregulation during tumorigenesis, but the molecular mechanisms underlying this process remain unclear. Here, we identify an enhancer cluster required for normal development that is aberrantly activated in breast and lung adenocarcinoma. Deletion of the SRR124-134 cluster disrupts expression of the SOX2 oncogene, dysregulates genome-wide transcription and chromatin accessibility and reduces the ability of cancer cells to form colonies in vitro. Analysis of primary tumors reveals a correlation between chromatin accessibility at this cluster and SOX2 overexpression in breast and lung cancer patients. We demonstrate that FOXA1 is an activator and NFIB is a repressor of SRR124-134 activity and SOX2 transcription in cancer cells, revealing a co-opting of the regulatory mechanisms involved in early development. Notably, we show that the conserved SRR124 and SRR134 regions are essential during mouse development, where homozygous deletion results in the lethal failure of esophageal-tracheal separation. These findings provide insights into how developmental enhancers can be reprogrammed during tumorigenesis and underscore the importance of understanding enhancer dynamics during development and disease.

NFIB facilitates replication licensing by acting as a genome organizer

The chromatin-based rule governing the selection and activation of replication origins in metazoans remains to be investigated. Here we report that NFIB, a member of Nuclear Factor I (NFI) family that was initially purified in host cells to promote adenoviral DNA replication but has since mainly been investigated in transcription regulation, is physically associated with the pre-replication complex (pre-RC) in mammalian cells. Genomic analyses reveal that NFIB facilitates the assembly of the pre-RC by increasing chromatin accessibility. Nucleosome binding and single-molecule magnetic tweezers shows that NFIB binds to and opens up nucleosomes. Transmission electron microscopy indicates that NFIB promotes nucleosome eviction on parental chromatin. NFIB deficiency leads to alterations of chromosome contacts/compartments in both G1 and S phase and affects the firing of a subset of origins at early-replication domains. Significantly, cancer-associated NFIB overexpression provokes gene duplication and genomic alterations recapitulating the genetic aberrance in clinical breast cancer and empowering cancer cells to dynamically evolve growth advantage and drug resistance. Together, these results point a role for NFIB in facilitating replication licensing by acting as a genome organizer, shedding new lights on the biological function of NFIB and on the replication origin selection in eukaryotes.

Downregulation of miR-182-5p by NFIB promotes NAD+ salvage synthesis in colorectal cancer by targeting NAMPT

Nuclear factor I B (NFIB) plays an important role in tumors. Our previous study found that NFIB can promote colorectal cancer (CRC) cell proliferation in acidic environments. However, its biological functions and the underlying mechanism in CRC are incompletely understood. Nicotinamide adenine dinucleotide (NAD+) effectively affects cancer cell proliferation. Nevertheless, the regulatory mechanism of NAD+ synthesis in cancer remains to be elucidated. Here we show NFIB promotes CRC proliferation in vitro and growth in vivo, and down-regulation of NFIB can reduce the level of NAD+. In addition, supplementation of NAD+ precursor NMN can recapture cell proliferation in CRC cells with NFIB knockdown. Mechanistically, we identified that NFIB promotes CRC cell proliferation by inhibiting miRNA-182-5p targeting and binding to NAMPT, the NAD+ salvage synthetic rate-limiting enzyme. Our results delineate a combination of high expression of NFIB and NAMPT predicted a clinical poorest prognosis. This work provides potential therapeutic targets for CRC treatment.

Salivary glands adenoid cystic carcinoma: a molecular profile update and potential implications

Adenoid cystic carcinoma (ACC) is an aggressive tumor with a high propensity for distant metastasis and perineural invasion. This tumor is more commonly found in regions of the head and neck, mainly the salivary glands. In general, the primary treatment modality for ACC is surgical resection and, in some cases, postoperative radiotherapy. However, no effective systemic treatment is available for patients with advanced disease. Furthermore, this tumor type is characterized by recurrent molecular alterations, especially rearrangements involving the MYB, MYBL1, and NFIB genes. In addition, they also reported copy number alterations (CNAs) that impact genes. One of them is C-KIT, mutations that affect signaling pathways such as NOTCH, PI3KCA, and PTEN, as well as alterations in chromatin remodeling genes. The identification of new molecular targets enables the development of specific therapies. Despite ongoing investigations into immunotherapy, tyrosine kinase inhibitors, and anti-angiogenics, no systemic therapy is approved by the FDA for ACC. In this review, we report the genetic and cytogenetic findings on head and neck ACC, highlighting possible targets for therapeutic interventions.

Transcriptional regulation of NDUFA4L2 by NFIB induces sorafenib resistance by decreasing reactive oxygen species in hepatocellular carcinoma

Sorafenib is one a first-line therapeutic drugs for advanced hepatocellular carcinoma (HCC). However, only 30% of patients benefit from sorafenib due to drug resistance. We and other groups have revealed that nuclear factor I B (NFIB) regulates liver regeneration and carcinogenesis, but its role in drug resistance is poorly known. We found that NFIB was more upregulated in sorafenib-resistant SMMC-7721 cells compared to parental cells. NFIB knockdown not only sensitized drug-resistant cells to sorafenib but also inhibited the proliferation and invasion of these cells. Meanwhile, NFIB promoted the proliferation and invasion of HCC cells in vitro and facilitated tumor growth and metastasis in vivo. Knocking down NFIB synergetically inhibited tumor growth with sorafenib. Mechanically, gene expression profiling and subsequent verification experiments proved that NFIB could bind with the promoter region of a complex I inhibitor NDUFA4L2 and promote its transcription. Transcriptional upregulation of NDUFA4L2 by NFIB could thus inhibit the sorafenib-induced reactive oxygen species accumulation. Finally, we found that NFIB was highly expressed in HCC tissues, and high NFIB expression level was associated with macrovascular invasion, advanced tumor stage, and poor prognosis of HCC patients (n = 156). In summary, we demonstrated that NFIB could transcriptionally upregulate NDUFA4L2 to enhance both intrinsic and acquired sorafenib resistance of HCC cells by reducing reactive oxygen species induction.

NFIXing Cancer: The Role of NFIX in Oxidative Stress Response and Cell Fate

NFIX, a member of the nuclear factor I (NFI) family of transcription factors, is known to be involved in muscle and central nervous system embryonic development. However, its expression in adults is limited. Similar to other developmental transcription factors, NFIX has been found to be altered in tumors, often promoting pro-tumorigenic functions, such as leading to proliferation, differentiation, and migration. However, some studies suggest that NFIX can also have a tumor suppressor role, indicating a complex and cancer-type dependent role of NFIX. This complexity may be linked to the multiple processes at play in regulating NFIX, which include transcriptional, post-transcriptional, and post-translational processes. Moreover, other features of NFIX, including its ability to interact with different NFI members to form homodimers or heterodimers, therefore allowing the transcription of different target genes, and its ability to sense oxidative stress, can also modulate its function. In this review, we examine different aspects of NFIX regulation, first in development and then in cancer, highlighting the important role of NFIX in oxidative stress and cell fate regulation in tumors. Moreover, we propose different mechanisms through which oxidative stress regulates NFIX transcription and function, underlining NFIX as a key factor for tumorigenesis.

MicroRNA-377: A therapeutic and diagnostic tumor marker

Cancer is considered as one of the main causes of human deaths globally. Despite the recent progresses in therapeutic modalities, there is still a high rate of mortality among cancer patients. Late diagnosis in advanced tumor stages is one of the main reasons for treatment failure in cancer patients. Therefore, it is required to suggest the novel strategies for the early tumor detection. MicroRNAs (miRNAs) have critical roles in neoplastic transformation by regulation of cell proliferation, migration, and apoptosis. They are always considered as non-invasive markers due to their high stability in body fluids. Since, all of the miRNAs have tissue-specific functions in different tumors as tumor suppressor or oncogene; it is required to investigate the molecular mechanisms of every miRNA in different tumors to introduce that as a suitable non-invasive diagnostic marker in cancer patients. For the first time in the present review, we discussed the role of miR-377 during tumor progression. It has been reported that miR-377 mainly functions as a tumor suppressor through the regulation of signaling pathways and transcription factors. This review is an important step toward introducing the miR-377 as a novel diagnostic marker as well as a therapeutic target in cancer patients.

The NFIB/CARM1 partnership is a driver in preclinical models of small cell lung cancer

The coactivator associated arginine methyltransferase (CARM1) promotes transcription, as its name implies. It does so by modifying histones and chromatin bound proteins. We identified nuclear factor I B (NFIB) as a CARM1 substrate and show that this transcription factor utilizes CARM1 as a coactivator. Biochemical studies reveal that tripartite motif 29 (TRIM29) is an effector molecule for methylated NFIB. Importantly, NFIB harbors both oncogenic and metastatic activities, and is often overexpressed in small cell lung cancer (SCLC). Here, we explore the possibility that CARM1 methylation of NFIB is important for its transforming activity. Using a SCLC mouse model, we show that both CARM1 and the CARM1 methylation site on NFIB are critical for the rapid onset of SCLC. Furthermore, CARM1 and methylated NFIB are responsible for maintaining similar open chromatin states in tumors. Together, these findings suggest that CARM1 might be a therapeutic target for SCLC.

iCancer-Pred: A tool for identifying cancer and its type using DNA methylation

DNA methylation is an important epigenetics, which occurs in the early stages of tumor formation. And it also is of great significance to find the relationship between DNA methylation and cancer. This paper proposes a novel model, iCancer-Pred, to identify cancer and classify its types further. The datasets of DNA methylation information of 7 cancer types have been collected from The Cancer Genome Atlas (TCGA). The coefficient of variation firstly is used to reduce the number of features, and then the elastic network is applied to select important features. Finally, a fully connected neural network is constructed with these selected features. In predicting seven types of cancers, iCancer-Pred has achieved an overall accuracy of over 97% accuracy with 5-fold cross-validation. For the convenience of the application, a user-friendly web server: http://bioinfo.jcu.edu.cn/cancer or http://121.36.221.79/cancer/ is available. And the source codes are freely available for download at https://github.com/Huerhu/iCancer-Pred.

Malignant Transformation of Giant Cell Tumour of Bone: A Review of Literature and the Experience of a Referral Centre

Giant cell tumour of bone (GCTB) is a benign, locally aggressive primary bone neoplasm that represents 5% of all bone tumours. The principal treatment approach is surgery. Although generally GCTB is considered only a locally aggressive disease, it can metastasise, and lung metastases occur in 1–9% of patients. To date, only the use of denosumab has been approved as medical treatment for GCTB. Even more rarely, GCTB undergoes sarcomatous transformation into a malignant tumour (4% of all GCTB), but history of this malignant transformation is unclear and unpredictable. Considering the rarity of the event, the data in the literature are few. In this review, we summarise published data of GCTB malignant transformation and we analyse three cases of malignant transformation of GCTB, evaluating histopathology, genetics, and radiological aspects. Despite the rarity of this event, we conclude that a strict follow up is recommended to detect early malignant transformation.

Cytochrome P450 polymorphism: From evolution to clinical use

The cytochromes P450s can be divided in two groups, those of high importance for endogenous functions being evolutionary quite stable and those participating in detoxification of drugs and other xenobiotics having less important endogenous functions. In the latter group extensive genetic diversity has been allowed and in addition this is of high importance for survival in different environments. The genetic polymorphisms in these genes have evolved to some extent based on dietary restrictions and environmental factors and have not been subject of conservation due to less importance for survival. In cases of high dietary selection events, gene multiplication and amplification events have been seen. The different variants in genes encoding drug metabolizing enzymes can be used as genetic biomarkers (pharmacogenomic labels) for adjustment of drug treatment leading to less adverse drug reactions and better response. Indeed, this has improved the use of personalized medicine, although the missing heredity seen based on twin studies indicates that there are indeed many more genetic variants to be discovered before one can achieve a satisfactory relationship between genotype and phenotype with respect to drug metabolism and toxicity.

Exosomal miR-626 promotes the malignant behavior of oral cancer cells by targeting NFIB

BACKGROUND

Tumor-derived exosomes, as emerging regulators of intercellular communication, are important for tumorigenesis and development in multiple tumors. The purpose of this study was to investigate whether exosomal miR-626 exists. More importantly, if exosomal miR-626 exists, the mechanism by which it is transferred into neighboring cancer cells and contributes to tumor progression needs to be clarified.

METHODS AND RESULTS

The expression of miRNA and mRNA are analyzed by RT-qPCR. Proliferation, colony formation, wound healing, cell cycle are carried out to assess the function of exosomal miR-626. Furthermore, a xenograft experiment is utilized to conform the cancer-promoting role of exosomal miR-626 in oral cancer. Here, we showed that miR-626 is upregulated in oral cancer-derived exosomes and can be transferred between oral cancer cells. Exosomal miR-626 promotes cancer cell proliferation, colony formation, migration and G0/G1-to-S phase transition. Nuclear factor I/B (NFIB), a tumor suppressor gene in various cancers, was predicted to be a potential target of miR-626 by using three algorithms. Luciferase reporter assay data revealed that miR-626 can directly bind to the 3'-UTR of NFIB and subsequently suppress its expression and downstream signaling. Restoration of NFIB expression rescued the malignant phenotype induced by exosomal miR-626. In addition, exosomal miR-626 administration facilitated cancer growth in a xenograft tumor model, accompanied by downregulation of NFIB expression.

CONCLUSIONS

Our data demonstrate that exosomal miR-626 can facilitate the development of oral cancer by inhibiting the expression of its target NFIB. Exosomal miR-626 might be a therapeutic target for oral cancer.

Hepatocyte-Specific Knock-Out of Nfib Aggravates Hepatocellular Tumorigenesis via Enhancing Urea Cycle

Nuclear Factor I B (NFIB) has been reported to promote tumor growth, metastasis, and liver regeneration, but its mechanism in liver cancer is not fully elucidated. The present study aims to reveal the role of NFIB in hepatocellular carcinogenesis. In our study, we constructed hepatocyte-specific NFIB gene knockout mice with CRISPR/Cas9 technology (Nfib^-/-; Alb-cre), and induced liver cancer mouse model by intraperitoneal injection of DEN/CCl₄. First, we found that Nfib^-/- mice developed more tumor nodules and had heavier livers than wild-type mice. H&E staining indicated that the liver histological severity of Nfib^-/- group was more serious than that of WT group. Then we found that the differentially expressed genes in the tumor tissue between Nfib^-/- mice and wild type mice were enriched in urea cycle. Furthermore, ASS1 and CPS1, the core enzymes of the urea cycle, were significantly upregulated in Nfib^-/- tumors. Subsequently, we validated that the expression of ASS1 and CPS1 increased after knockdown of NFIB by lentivirus in normal hepatocytes and also promoted cell proliferation in vitro. In addition, ChIP assay confirmed that NFIB can bind with promoter region of both ASS1 and CPS1 gene. Our study reveals for the first time that hepatocyte-specific knock-out of Nfib aggravates hepatocellular tumor development by enhancing the urea cycle.

Secondary Malignancy in Giant Cell Tumor: A Single-Center Study

Giant cell tumor of bone (GCTB) undergoes a sarcomatous transformation. Secondary malignancy in giant cell tumor (MGCT) is associated with radiotherapy and has a dismal prognosis. We reviewed medical records to investigate the clinicopathological characteristics and prognosis of MGCT patients. The enrollment criterion was high-grade spindle-cell sarcoma, which developed at the site of prior GCTB treatment. Twelve patients were analyzed: six females and six males. The median age was 42.5 years. Benign recurrence occurred in five GCTB patients not treated with radiotherapy. No pulmonary implants were observed. The median latency to the malignant transformation was 63 months. Nine patients were AJCC stage IIB, and three were stage IVA. The median follow-up period after malignant transformation was 62.5 months. Five patients developed local recurrence, and six had distant metastasis. Five-year overall recurrence and metastasis-free survival rates were 61.9%, 66.7%, and 58.3%, respectively. Initial metastasis was a predictive factor for overall survival. Benign local recurrence of GCTB was also a negative factor for metastasis-free survival of MGCT patients. Differences in overall survival according to benign recurrence also showed a tendency toward significance. In our series, secondary MGCT did not occur after radiotherapy. The prognosis was better than previous findings. Benign recurrence of GCTB could reflect the prognosis of MGCT.

Sevoflurane inhibits the malignant phenotypes of glioma through regulating miR-146b-5p/NFIB axis

PURPOSE

Sevoflurane is a common used inhaled anesthetic that was reported to regulate the progression of multiple cancers. Here, we aimed to investigate the function and regulatory mechanism underlying sevoflurane in glioma cells.

METHODS

A172 and U251 cells were treated with different concentrations of sevoflurane. Colony formation, EdU satining and 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT), flow cytometry, and transwell assays were performed to evaluate cell proliferation, apoptosis, migration and invasion, respectively. Circ_VCAN, microRNA-146b-5p (miR-146b-5p) and nuclear factor I B (NFIB) expression levels were assessed by real-time quantitative PCR (RT-qPCR) or western blot. Bioinformatics analysis and dual-luciferase reporter assay were applied to evaluate the correlation between miR-146b-5p and circ_VCAN or NFIB. A xenograft glioma mice model was established to verify the effect of sevoflurane on tumor growth in vivo.

RESULTS

Sevoflurane (Sev) inhibited proliferation, migration, invasion, and elevated apoptosis of A172 and U251 cells. Sevoflurane treatment inhibited the expression of circ_VCAN and NFIB, but elevated the expression of miR-146b-5p in glioma cells. Overexpression of circ_VCAN alleviated the inhibition effects of sevoflurane on the malignant phenotypes of glioma in vitro and in vivo. Besides, miR-146b-5p is a target of circ_VCAN and negatively regulated NFIB expression. Overexpression of miR-146b-5p partly reversed the effects of circ_VCAN in Sev-treated glioma cells. Furthermore, miR-146b-5p deletion enhanced glioma progression in sevoflurane treated glioma cells by targeting NFIB. Moreover, circ_VCAN could upregulate NFIB expression by sponging miR-146b-5p in Sev-treated glioma cells.

CONCLUSION

Sevoflurane alleviated proliferation, migration and invasion, but enhanced apoptosis of glioma cells through regulating circ_VCAN/miR-146b-5p/NFIB axis.

NFI transcriptionally represses CDON and is required for SH-SY5Y cell survival

Nuclear Factor One (NFI) family of transcription factors regulate proliferation and multiple aspects of differentiation, playing analogous roles in embryonic development and various types of cancer. While all NFI family members are expressed in the developing brain and are involved in progression of brain cancers, their role in neuroblastoma has not been studied. Here we show that NFIB is required for the survival and proliferation of SH-SY5Y neuroblastoma cells, assessed by viability and colony formation assays. Cdon, an Ig superfamily member, is a SHH dependence receptor that acts as a tumor suppressor in neuroblastoma. In the absence of NFI, Cdon is upregulated in the developing mouse brain, however the mechanisms by which its transcription is regulated remains unknown. We report CDON as a downstream target of NFIs in SH-SY5Y cells. There are three putative NFI binding sites within the one kb CDON promoter, two of which are occupied by NFIs in SH-SY5Y cells and human neural stem cells. In dual-luciferase assays, Nfib directly represses CDON proximal promoter activity. Moreover, silencing NFIB leads to upregulation of CDON in SH-SY5Y cells, however, decreased cell proliferation in NFIB silenced cells could not be rescued by concomitantly silencing CDON, suggesting other molecular players are involved. For instance, p21, an NFI target in glioblastoma and breast cancer cells, is also upregulated upon NFIB knock-down. We propose that NFIB is indispensable for SH-SY5Y cells which may involve regulation of apoptosis inducer proteins CDON and p21.

Nfib promotes chondrocyte proliferation and inhibits differentiation by mildly regulating Sox9 and its downstream genes

BACKGROUND

Chondrocyte proliferation and differentiation play pivotal roles in regulating cartilage formation, endochondral bone formation, and repair. Cartilage damage and underdevelopment may cause severe joint diseases. Various transcription factors regulate cartilage development. Nuclear factor 1 B (Nfib) is a transcription factor that plays a regulatory role in various organs. However, the effect and mechanism of Nfib on the proliferation and differentiation of chondrocytes in cartilage are still largely unknown.

METHODS AND RESULTS

In the present study, we investigated the gene expression patterns in primary chondrocytes with Nfib overexpression or silencing by RNA sequencing (RNA-seq) technology. The results showed that Nfib overexpression significantly up-regulated genes that are related to chondrocyte proliferation and extracellular matrix (ECM) synthesis and significantly down-regulated genes related to chondrocyte differentiation and ECM degradation. However, with Nfib silencing, the genes involved in promoting chondrocyte differentiation were significantly up-regulated, whereas those involved in promoting chondrocyte proliferation were significantly down-regulated. Furthermore, quantitative real-time PCR (qRT-PCR), western blot, alcian blue staining and immunofluorescence staining assays further confirmed that Nfib potentially promotes chondrocyte proliferation and extracellular synthesis but inhibits differentiation.

CONCLUSIONS

The molecular mechanism of Nfib in promoting chondrocyte proliferation and inhibiting differentiation was probably achieved by stimulating Sox9 and its downstream genes. Thus, this study adds new insights regarding the underlying molecular mechanism of transcriptional regulation in cartilage.

Circ_0069718 promotes the progression of breast cancer by up-regulating NFIB through sequestering miR-590-5p

Researches indicate that circular RNAs are dysregulated in breast cancer (BC) and play a critical role in regulating the malignant phenotype of cancer cells. Herein, the goal of this work was to investigate the role and mechanism of circ_0069718 in BC development. Levels of genes and proteins were detected by quantitative real-time polymerase chain reaction and western blot. In vitro experiments were performed using cell counting kit-8 assay, colony formation assay, EdU (5-ethynyl-2'-deoxyuridine) assay, flow cytometry, western blot, and transwell assay, respectively. The dual-luciferase reporter and RNA immunoprecipitation assays were used to identify the target relationship between miR-590-5p and circ_0069718 or nuclear factor I/B (NFIB). In vivo experiments were conducted using Xenograft model in mice. Circ_0069718 was up-regulated in BC tissues and cells. Knockdown of circ_0069718 suppressed BC cell apoptosis, migration, and invasion in vitro effectively. Mechanistically, circ_0069718 directly targeted miR-590-5p to up-regulate its target NFIB. Rescue experiments showed that miR-590-5p inhibition reversed the inhibitory effects of circ_0069718 knockdown on BC cell-aggressive oncogenic phenotypes; moreover, miR-590-5p re-expression restrained BC cell proliferation and mobility, which were abolished by NFIB up-regulation. Besides that, circ_0069718 silencing hindered tumor growth via miR-590-5p/NFIB axis in vivo. Circ_0069718 promotes BC progression by up-regulating NFIB through sequestering miR-590-5p, suggesting a potential therapeutic strategy in BC.

Sex-Specific Social Behavior and Amygdala Proteomic Deficits in Foxp2 +/- Mutant Mice

In humans, mutations in the transcription factor encoding gene, FOXP2, are associated with language and Autism Spectrum Disorders (ASD), the latter characterized by deficits in social interactions. However, little is known regarding the function of Foxp2 in male or female social behavior. Our previous studies in mice revealed high expression of Foxp2 within the medial subnucleus of the amygdala (MeA), a limbic brain region highly implicated in innate social behaviors such as mating, aggression, and parental care. Here, using a comprehensive panel of behavioral tests in male and female Foxp2 +/- heterozygous mice, we investigated the role Foxp2 plays in MeA-linked innate social behaviors. We reveal significant deficits in olfactory processing, social interaction, mating, aggressive, and parental behaviors. Interestingly, some of these deficits are displayed in a sex-specific manner. To examine the consequences of Foxp2 loss of function specifically in the MeA, we conducted a proteomic analysis of microdissected MeA tissue. This analyses revealed putative sex differences expression of a host of proteins implicated in neuronal communication, connectivity, and dopamine signaling. Consistent with this, we discovered that MeA Foxp2-lineage cells were responsive to dopamine with differences between males and females. Thus, our findings reveal a central and sex-specific role for Foxp2 in social behavior and MeA function.

The NFIB-ERO1A axis promotes breast cancer metastatic colonization of disseminated tumour cells

Metastasis is the main cause of deaths related to solid cancers. Active transcriptional programmes are known to regulate the metastatic cascade but the molecular determinants of metastatic colonization remain elusive. Using an inducible piggyBac (PB) transposon mutagenesis screen, we have shown that overexpression of the transcription factor nuclear factor IB (NFIB) alone is sufficient to enhance primary mammary tumour growth and lung metastatic colonization. Mechanistically and functionally, NFIB directly increases expression of the oxidoreductase ERO1A, which enhances HIF1α-VEGFA-mediated angiogenesis and colonization, the last and fatal step of the metastatic cascade. NFIB is thus clinically relevant: it is preferentially expressed in the poor-prognostic group of basal-like breast cancers, and high expression of the NFIB/ERO1A/VEGFA pathway correlates with reduced breast cancer patient survival.

NFIB promotes the progression of gastric cancer by upregulating circMAP7D1 to stabilize HER2 mRNA

The present study evaluated the expression levels of nuclear factor I B (NFIB) in gastric cancer (GC) specimens and cells, and its regulatory roles were further elucidated. The expression levels of NFIB were examined in GC and paired normal specimens, and in human GC and normal gastric epithelial cells by reverse transcription‑quantitative PCR. A circular RNA (circRNA) microarray was performed to identify the novel downstream circRNA of NFIB. Cell proliferation was determined by Cell Counting Kit‑8 assay. Furthermore, cell cycle distribution and apoptosis were assessed using flow cytometry. Interactions between RNA were examined by RNA pulldown assay and the stability of target mRNA was evaluated using a mRNA stability assay. The results of the present study revealed that NFIB was upregulated in GC. Furthermore, silencing NFIB suppressed the proliferation of GC cells, whereas cell cycle arrest and apoptosis were enhanced. In addition, significant downregulation of circMAP7D1 (hsa_circ_0004093) was observed in GC cells infected with short hairpin RNA‑NFIB. These findings indicated that circMAP7D1 may be a promising downstream molecule of NFIB in GC, and further functional analyses indicated that circMAP7D1 was involved in NFIB‑modulated GC cell proliferation and apoptosis. Moreover, human epidermal growth factor receptor 2 (HER2) was identified as a novel target of circMAP7D1 in GC, and NFIB was able to increase the stability of HER2 mRNA through regulating circMAP7D1. In conclusion, the present findings indicated that NFIB expression was increased in GC. In addition, NFIB may promote the proliferation of GC cells and function through stabilizing HER2 mRNA by upregulating circMAP7D1. Notably, NFIB and its novel downstream signaling pathway may serve essential roles during the development of GC, and NFIB may be considered a promising candidate for the treatment of patients with GC.

Establishment of the TALE-code reveals aberrantly activated homeobox gene PBX1 in Hodgkin lymphoma

Homeobox genes encode transcription factors which regulate basic processes in development and cell differentiation and are grouped into classes and subclasses according to sequence similarities. Here, we analyzed the activities of the 20 members strong TALE homeobox gene class in early hematopoiesis and in lymphopoiesis including developing and mature B-cells, T-cells, natural killer (NK)-cells and innate lymphoid cells (ILC). The resultant expression pattern comprised eleven genes and which we termed TALE-code enables discrimination of normal and aberrant activities of TALE homeobox genes in lymphoid malignancies. Subsequent expression analysis of TALE homeobox genes in public datasets of Hodgkin lymphoma (HL) patients revealed overexpression of IRX3, IRX4, MEIS1, MEIS3, PBX1, PBX4 and TGIF1. As paradigm we focused on PBX1 which was deregulated in about 17% HL patients. Normal PBX1 expression was restricted to hematopoietic stem cells and progenitors of T-cells and ILCs but absent in B-cells, reflecting its roles in stemness and early differentiation. HL cell line SUP-HD1 expressed enhanced PBX1 levels and served as an in vitro model to identify upstream regulators and downstream targets in this malignancy. Genomic studies of this cell line therein showed a gain of the PBX1 locus at 1q23 which may underlie its aberrant expression. Comparative expression profiling analyses of HL patients and cell lines followed by knockdown experiments revealed NFIB and TLX2 as target genes activated by PBX1. HOX proteins operate as cofactors of PBX1. Accordingly, our data showed that HOXB9 overexpressed in HL coactivated TLX2 but not NFIB while activating TNFRSF9 without PBX1. Further downstream analyses showed that TLX2 activated TBX15 which operated anti-apoptotically. Taken together, we discovered a lymphoid TALE-code and identified an aberrant network around deregulated TALE homeobox gene PBX1 which may disturb B-cell differentiation in HL by reactivation of progenitor-specific genes. These findings may provide the framework for future studies to exploit possible vulnerabilities of malignant cells in therapeutic scenarios.

Nuclear factor I/B mediates epithelial-mesenchymal transition in human melanoma cells through ZEB1

The relationship between nuclear factor I/B (NFIB) and cancer attracts growing research interest. NFIB has diverse and specific roles in tumor progression and invasion. However, the potential effects and functions of this transcription factor in melanoma remain unclear. The present study sought to determine the distinguishing properties of NFIB in melanoma cells. Immunohistochemical examination of the tissues of 15 patients with melanoma indicated that the expression of NFIB was high in melanoma specimens, compared with the benign nevus and normal skin specimens. In addition, the relationship between high NFIB expression and low overall survival rate was assessed. Functional studies demonstrated that NFIB enhanced the malignancy of melanoma, including proliferation, migration and invasion. In addition, NFIB silencing in A375 and A875 cell lines inhibited the process of epithelial-mesenchymal transition (EMT), upregulated E-cadherin and zona occludens-1, but suppressed N-cadherin and vimentin expression. These findings may suggest a new function of NFIB in promoting the migration and invasion of melanoma cells. Therefore, the present study further evaluated the association between NFIB and zinc finger protein E-box binding homeobox-1 (ZEB1) in melanoma. Mechanistic experiments revealed that NFIB exerted its roles during EMT by regulating ZEB1. Overall, the present data indicates that NFIB promotes the malignancy of melanoma, particularly EMT, by modulating the ZEB1 axis, such as ZEB2, ATM and CHK1, which may represent a potential molecular therapeutic target in melanoma.

Denosumab in Giant Cell Tumor of Bone: Current Status and Pitfalls

Denosumab is a monoclonal antibody against RANK ligand for treatment of giant cell tumor of bone (GCTB). Clinical trials and case series have demonstrated that denosumab is relevant to beneficial tumor response and surgical down-staging in patients of GCTB. However, these trials or case series have limitations with a short follow-up. Recent increasing studies revealed that denosumab probably increased the local recurrence risk in patients treated with curettage. This may be caused by the thicken bone margin of tumor that trapped tumor cells from curettage. The direct bone formation by tumor cells in the margin after denosumab treatment also contributed to the local recurrence. in vitro studies showed denosumab resulted in a cytostatic instead of a true cytotoxic response on neoplastic stromal cells. More importantly, denosumab-treated GCTB exhibited morphologic overlap with malignancy, and a growing number of patients of malignant transformation of GCTB during denosumab treatment have been reported. The optimal duration, long term safety, maintenance dose, and optimum indications remain to be elucidated. With these concerns in mind, this review warns that the denosumab therapy of GCTB should be applied with caution.

NFIB functions as an oncogene in estrogen receptor-positive breast cancer and is regulated by miR-205-5p

Nuclear factor I/B(NFIB) is a prominent transcription factor that plays a critical role in cancer progression. In this study, we found that the protein level of NFIB was significantly upregulated in estrogen receptor (ER) positive breast cancer tissues compared to matched adjacent noncancerous tissues while the NFIB mRNA expression level was not obviously dysregulated. Similarly, ER-positive breast cancer cell line, MCF7 express a high protein level of NFIB, while the mRNA level is not significantly upregulated. The function assays indicated that NFIB promoted MCF-7 cell cycle progression, cell proliferation and suppressed apoptosis in vitro. Furthermore, we explored the molecular mechanisms of NFIB as a target gene of miR-205-5p. Finally, we found that miR-205-5p was significantly downregulated in ER -positive breast cancer, and had the opposite eff ;ects on breast cancer cells compared with NFIB. Taken together, this study highlighted the molecular mechanisms of NFIB as an oncogene in ER-positive breast cancer, which was negatively regulated by miR-205-5p in breast cancer.

MicroRNA-138-5p targets the NFIB-Snail1 axis to inhibit colorectal cancer cell migration and chemoresistance

Background

Colorectal cancer ranks among the most lethal diseases worldwide. Although much progress has been made in research and treatment of colorectal cancer in recent years, the underlying mechanisms related to migration of the cancer cells and the reason for chemoresistance still remain unclear. In this research, we explored the underlying effect of miR-138-5p in colorectal cancer.

Methods

We used qRT-PCR to investigate the expression of miR-138-5p, Snail1, NFIB in colorectal cancer cells. Lentiviral vectors containing miR-138-5p mimics and inhibitors were constructed and transfected cells. Wound healing assay was applied to illustrate interferences on cell migration. Fluorouracial, doxorubicin, cisplat in were used to detect chemotherapy resistance. In order to identify target genes, bioinformatic methods were applied. Snail1 and NFIB protein expression in stable cell lines was detected using Western blot. Double luciferase and CHIP experiment were used to verify binding sites. We used rescue experiments to further explore the interactions among Snail1, NFIB and miR-138-5p.

Results

The expression of miR-138-5p in colorectal cancer cells was low. miR-138-5p inhibited cell migration in colorectal cancer, and could negatively regulate chemotherapy resistance. miR-138-5p targeted NFIB, and regulated Snail1 expression, which mediated colorectal cancer cell migration and chemotherapy resistance.

Conclusions

Our research indicates that miR-138-5p could be a crucial modulator controlling colorectal cancer cell migration and chemoresistance, by acting upon the NFIB-Snail1 axis. miR-138-5p has an emerging prospect to be exploited as a new target for colorectal cancer.

Activation of PLAG1 and HMGA2 by gene fusions involving the transcriptional regulator gene NFIB

The pleomorphic adenoma (PA), which is the most common salivary gland neoplasm, is a benign tumor characterized by recurrent chromosome rearrangements involving 8q12 and 12q14-15. We have previously shown that the PLAG1 and HMGA2 oncogenes are the targets of these rearrangements. Here, we have identified previously unrecognized subsets of PAs with ins(9;8)/t(8;9) (n = 5) and ins(9;12)/t(9;12) (n = 8) and breakpoints located in the vicinity of the PLAG1 and HMGA2 loci. RNA-sequencing and reverse transcriptase (RT)-PCR analyses of a case with an ins(9;8) revealed a novel NFIB-PLAG1 fusion in which NFIB exon 4 is linked to PLAG1 exon 3. In contrast to the developmentally regulated PLAG1 gene, NFIB was highly expressed in normal salivary gland, indicating that PLAG1 in this case, as in other variant fusions, is activated by promoter swapping. RT-PCR analysis of three PAs with t(9;12) revealed two tumors with chimeric transcripts consisting of HMGA2 exon 4 linked to NFIB exons 9 or 3 and one case with a fusion linking HMGA2 exon 3 to NFIB exon 9. The NFIB fusion events resulted in potent activation of PLAG1 and HMGA2. Analysis of the chromatin landscape surrounding NFIB revealed several super-enhancers in the 5'- and 3'-parts of the NFIB locus and its flanking sequences. These findings indicate that PLAG1 and HMGA2, similar to MYB in adenoid cystic carcinoma, may be activated by enhancer-hijacking events, in which super-enhancers in NFIB are translocated upstream of PLAG1 or downstream of HMGA2. Our results further emphasize the role of NFIB as a fusion partner to multiple oncogenes in histopathologically different types of salivary gland tumors.

BAP1 functions as a tumor promoter in prostate cancer cells through EMT regulation

BRCA1-associated protein 1 (BAP1) is a deubiquitinating enzyme that has long been considered to be a tumor suppressor in various tumors, including renal cell carcinoma, uveal melanoma, mesothelioma, and cutaneous melanoma. However, the involvement of BAP1 in the progression of prostate cancer has not been studied until recently. Herein, we investigated the tumor promoting function of BAP1 in the context of prostate cancer. Analysis of The Cancer Genome Atlas (TCGA) data set showed that prostate cancer patients express high levels of BAP1 mRNA. High BAP1 expression is inversely correlated with disease-free survival in patients with prostate cancer. Among the prostate cell lines tested, BAP1 expression was high in tumorigenic and metastatic cell lines, but was low in normal prostate cell line. Knockdown of BAP1 in PC3 or DU145 cells induced mesenchymal-to-epithelial transition (MET). Further, BAP1-knockdown resulted in decreased migration and invasion of PC3 and DU145 cells. Conversely, overexpression of BAP1 in RWPE1, a normal prostate cell line, induced the migratory and invasive properties. Collectively, our findings identified that BAP1 has a tumor promoting function in prostate cancer cells, and suggest that BAP1 can serve as a potential therapeutic target for prostate cancer.

ATR is a MYB regulated gene and potential therapeutic target in adenoid cystic carcinoma

Adenoid cystic carcinoma (ACC) is a rare cancer that preferentially occurs in the head and neck, breast, as well as in other sites. It is an aggressive cancer with high rates of recurrence and distant metastasis. Patients with advanced disease are generally incurable due to the lack of effective systemic therapies. Activation of the master transcriptional regulator MYB is the genomic hallmark of ACC. MYB activation occurs through chromosomal translocation, copy number gain or enhancer hijacking, and is the key driving event in the pathogenesis of ACC. However, the functional consequences of alternative mechanisms of MYB activation are still uncertain. Here, we show that overexpression of MYB or MYB-NFIB fusions leads to transformation of human glandular epithelial cells in vitro and results in analogous cellular and molecular consequences. MYB and MYB-NFIB expression led to increased cell proliferation and upregulation of genes involved in cell cycle control, DNA replication, and DNA repair. Notably, we identified the DNA-damage sensor kinase ATR, as a MYB downstream therapeutic target that is overexpressed in primary ACCs and ACC patient-derived xenografts (PDXs). Treatment with the clinical ATR kinase inhibitor VX-970 induced apoptosis in MYB-positive ACC cells and growth inhibition in ACC PDXs. To our knowledge, ATR is the first example of an actionable target downstream of MYB that could be further exploited for therapeutic opportunities in ACC patients. Our findings may also have implications for other types of neoplasms with activation of the MYB oncogene.

Adhesion molecules in gamete transport, fertilization, early embryonic development, and implantation-role in establishing a pregnancy in cattle: A review

Cell-cell adhesion molecules have critically important roles in the early events of reproduction including gamete transport, sperm-oocyte interaction, embryonic development, and implantation. Major adhesion molecules involved in reproduction include cadherins, integrins, and disintegrin and metalloprotease domain-containing (ADAM) proteins. ADAMs on the surface of sperm adhere to integrins on the oocyte in the initial stages of sperm-oocyte interaction and fusion. Cadherins act in early embryos to organize the inner cell mass and trophectoderm. The trophoblast and uterine endometrial epithelium variously express cadherins, integrins, trophinin, and selectin, which achieve apposition and attachment between the elongating conceptus and uterine epithelium before implantation. An overview of the major cell-cell adhesion molecules is presented and this is followed by examples of how adhesion molecules help shape early reproductive events. The argument is made that a deeper understanding of adhesion molecules and reproduction will inform new strategies that improve embryo survival and increase the efficiency of natural mating and assisted breeding in cattle.

Irradiated Human Fibroblasts as a Substitute Feeder Layer to Irradiated Mouse 3T3 for the Culture of Human Corneal Epithelial Cells: Impact on the Stability of the Transcription Factors Sp1 and NFI

Because of the worldwide shortage of graftable corneas, alternatives to restore visual impairments, such as the production of a functional human cornea by tissue engineering, have emerged. Self-renewal of the corneal epithelium through the maintenance of a sub-population of corneal stem cells is required to maintain the functionality of such a reconstructed cornea. We previously reported an association between stem cell differentiation and the level to which they express the transcription factors Sp1 and NFI. In this study, we investigated the impact of replacing irradiated 3T3 (i3T3) murine fibroblast feeder cells by irradiated human corneal fibroblasts (iHFL) on the expression of Sp1 and NFI and evaluated their contribution to the proliferative properties of human corneal epithelial cells (hCECs) in both monolayer cultures and human tissue engineered corneas (hTECs). hCECs co-cultured with iHFL could be maintained for up to two more passages than when they were grown with i3T3. Western Blot and electrophoretic mobility shift assays (EMSAs) revealed no significant difference in the feeder-layer dependent increase in Sp1 at both the protein and DNA binding level, respectively, between HCECs grown with either i3T3 or iHFL. On the other hand, a significant increase in the expression and DNA binding of NFI was observed at each subsequent passage when hCECs were co-cultured along with i3T3. These changes were found to result from an increased expression of the NFIA and NFIB isoforms in hCECs grown with i3T3. Exposure of hCECs to cycloheximide revealed an increased stability of NFIB that likely resulted from post-translational glycosylation of this protein when these cells were co-cultured with i3T3. In addition, iHFL were as efficient as i3T3 at preserving corneal, slow-cycling, epithelial stem cells in the basal epithelium of the reconstructed hTECs. Furthermore, we observed an increased expression of genes whose encoded products promote hCECs differentiation along several passages in hCECs co-cultured with either type of feeder layer. Therefore, the iHFL feeder layer appears to be the most effective at maintaining the proliferative properties of hCECs in culture most likely by preserving high levels of Sp1 and low levels of NFIB, which is known for its gene repressor and cell differentiation properties.

Histone Deacetylase 3 Governs Perinatal Cerebral Development via Neural Stem and Progenitor Cells

We report that cerebrum-specific inactivation of the histone deacetylase 3 (HDAC3) gene causes striking developmental defects in the neocortex, hippocampus, and corpus callosum; post-weaning lethality; and abnormal behaviors, including hyperactivity and anxiety. The defects are due to rapid loss of embryonic neural stem and progenitor cells (NSPCs). Premature neurogenesis and abnormal neuronal migration in the mutant brain alter NSPC homeostasis. Mutant cerebral cortices also display augmented DNA damage responses, apoptosis, and histone hyperacetylation. Moreover, mutant NSPCs are impaired in forming neurospheres in vitro, and treatment with the HDAC3-specific inhibitor RGFP966 abolishes neurosphere formation. Transcriptomic analyses of neonatal cerebral cortices and cultured neurospheres support that HDAC3 regulates transcriptional programs through interaction with different transcription factors, including NFIB. These findings establish HDAC3 as a major deacetylase critical for perinatal development of the mouse cerebrum and NSPCs, thereby suggesting a direct link of this enzymatic epigenetic regulator to human cerebral and intellectual development.

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HDAC3 inactivation causes developmental defects in the neocortex and hippocampus

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HDAC3 loss leads to depletion of embryonic neural stem and progenitor cells

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HDAC3 inhibition abolishes neurosphere formation in vitro

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HDAC3 interacts with NFIB and other transcription factors in cerebral development

IGF2/IGF1R Signaling as a Therapeutic Target in MYB-Positive Adenoid Cystic Carcinomas and Other Fusion Gene-Driven Tumors

Chromosome rearrangements resulting in pathogenetically important gene fusions are a common feature of many cancers. They are often potent oncogenic drivers and have key functions in central cellular processes and pathways and encode transcription factors, transcriptional co-regulators, growth factor receptors, tyrosine kinases, and chromatin modifiers. In addition to being useful diagnostic biomarkers, they are also targets for development of new molecularly targeted therapies. Studies in recent decades have shown that several oncogenic gene fusions interact with the insulin-like growth factor (IGF) signaling pathway. For example, the MYB-NFIB fusion in adenoid cystic carcinoma is regulated by IGF1R through an autocrine loop, and IGF1R is a downstream target of the EWSR1-WT1 and PAX3-FKHR fusions in desmoplastic small round cell tumors and alveolar rhabdomyosarcoma, respectively. Here, we will discuss the mechanisms behind the interactions between oncogenic gene fusions and the IGF signaling pathway. We will also discuss the role of therapeutic inhibition of IGF1R in fusion gene driven malignancies.

Effects of nuclear factor I phosphorylation on calpastatin (CAST) gene variant expression and subcellular distribution in malignant glioma cells

Malignant glioma (MG) is the most lethal primary brain tumor. In addition to having inherent resistance to radiation treatment and chemotherapy, MG cells are highly infiltrative, rendering focal therapies ineffective. Genes involved in MG cell migration and glial cell differentiation are up-regulated by hypophosphorylated nuclear factor I (NFI), which is dephosphorylated by the phosphatase calcineurin in MG cells. Calcineurin is cleaved and thereby activated by calpain proteases, which are, in turn, inhibited by calpastatin (CAST). Here, we show that the CAST gene is a target of NFI and has NFI-binding sites in its intron 3 region. We also found that NFI-mediated regulation of CAST depends on NFI's phosphorylation state. We noted that occupation of CAST intron 3 by hypophosphorylated NFI results in increased activation of an alternative promoter. This activation resulted in higher levels of CAST transcript variants, leading to increased levels of CAST protein that lacks the N-terminal XL domain. CAST was primarily present in the cytoplasm of NFI-hypophosphorylated MG cells, with a predominantly perinuclear immunostaining pattern. NFI knockdown in NFI-hypophosphorylated MG cells increased CAST levels at the plasma membrane. These results suggest that NFI plays an integral role in the regulation of CAST variants and CAST subcellular distribution. Along with the previous findings indicating that NFI activity is regulated by calcineurin, these results provide a foundation for further investigations into the possibility of regulatory cross-talk between NFI and the CAST/calpain/calcineurin signaling pathway in MG cells.

NFIB promotes cell survival by directly suppressing p21 transcription in TP53-mutated triple-negative breast cancer

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited treatment options and poor prognosis. There is an urgent need to identify and understand the key factors and signalling pathways driving TNBC tumour progression, relapse, and treatment resistance. In this study, we report that gene copy numbers and expression levels of nuclear factor IB (NFIB), a recently identified oncogene in small cell lung cancer, are preferentially increased in TNBC compared to other breast cancer subtypes. Furthermore, increased levels of NFIB are significantly associated with high tumour grade, poor prognosis, and reduced chemotherapy response. Concurrent TP53 mutations and NFIB overexpression (z-scores > 0) were observed in 77.9% of TNBCs, in contrast to 28.5% in non-TNBCs. Depletion of NFIB in TP53-mutated TNBC cell lines promotes cell death, cell cycle arrest, and enhances sensitivity to docetaxel, a first-line chemotherapeutic drug in breast cancer treatment. Importantly, these alterations in growth properties were accompanied by induction of CDKN1A, the gene encoding p21, a downstream effector of p53. We show that NFIB directly interacts with the CDKN1A promoter in TNBC cells. Furthermore, knockdown of combined p21 and NFIB reverses the docetaxel-induced cell growth inhibition observed upon NFIB knockdown, indicating that NFIB's effect on chemotherapeutic drug response is mediated through p21. Our results indicate that NFIB is an important TNBC factor that drives tumour cell growth and drug resistance, leading to poor clinical outcomes. Thus, targeting NFIB in TP53-mutated TNBC may reverse oncogenic properties associated with mutant p53 by restoring p21 activity. Copyright © 2018 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

Nuclear factor I/B promotes colorectal cancer cell proliferation, epithelial-mesenchymal transition and 5-fluorouracil resistance

Nuclear factor I/B (NFIB) is a widely studied transcription factor that participates in tumor progression; nevertheless, studies on NFIB in colorectal cancer (CRC) are limited. In our study, Western blot and RT‐PCR analyses showed that NFIB was overexpressed in CRC tissues and cell lines, which was consistent with our bioinformatic analysis results. Furthermore, NFIB expression was closely related to the TNM stage of CRC. NFIB promoted cell proliferation and migration and inhibited cell apoptosis in vitro. Meanwhile, we discovered that NFIB accelerated xenograft tumor growth in vivo. In addition, NFIB weakened the sensitivity of CRC cells to 5‐fluorouracil (5‐FU). NFIB induced epithelial‐mesenchymal transition (EMT) by upregulating snail expression, which was accompanied by decreased E‐cadherin and Zo‐1 expression and increasedd Vimentin expression. Because the Akt pathway plays an important role in CRC progression, we examined whether there was a correlation between NFIB and the Akt pathway in cell proliferation and migration. Our results showed that NFIB promoted cell proliferation and increased 5‐FU resistance by activating the Akt pathway. In summary, our findings suggested that NFIB induced EMT of CRC cells via upregulating snail expression and promoted cell proliferation and 5‐FU resistance by activating the Akt pathway.

Nuclear Factor One X in Development and Disease

The past decade has seen incredible advances in the field of stem cell biology that have greatly improved our understanding of development and provided important insights into pathological processes. Transcription factors (TFs) play a central role in mediating stem cell proliferation, quiescence, and differentiation. One TF that contributes to these processes is Nuclear Factor One X (NFIX). Recently, NFIX activity has been shown to be essential in multiple organ systems and to have important translational impacts for human health. Here, we describe recent studies showing the contribution of NFIX to muscle development and muscular dystrophies, hematopoiesis, cancer, and neural stem cell biology, highlighting the importance of this knowledge in the development of therapeutic targets.

Lung Cancers: Molecular Characterization, Clonal Heterogeneity and Evolution, and Cancer Stem Cells

Lung cancer causes the largest number of cancer-related deaths in the world. Most (85%) of lung cancers are classified as non-small-cell lung cancer (NSCLC) and small-cell lung cancer (15%) (SCLC). The 5-year survival rate for NSCLC patients remains very low (about 16% at 5 years). The two predominant NSCLC histological phenotypes are adenocarcinoma (ADC) and squamous cell carcinoma (LSQCC). ADCs display several recurrent genetic alterations, including: KRAS, BRAF and EGFR mutations; recurrent mutations and amplifications of several oncogenes, including ERBB2, MET, FGFR1 and FGFR2; fusion oncogenes involving ALK, ROS1, Neuregulin1 (NRG1) and RET. In LSQCC recurrent mutations of TP53, FGFR1, FGFR2, FGFR3, DDR2 and genes of the PI3K pathway have been detected, quantitative gene abnormalities of PTEN and CDKN2A. Developments in the characterization of lung cancer molecular abnormalities provided a strong rationale for new therapeutic options and for understanding the mechanisms of drug resistance. However, the complexity of lung cancer genomes is particularly high, as shown by deep-sequencing studies supporting the heterogeneity of lung tumors at cellular level, with sub-clones exhibiting different combinations of mutations. Molecular studies performed on lung tumors during treatment have shown the phenomenon of clonal evolution, thus supporting the occurrence of a temporal tumor heterogeneity.

Nfib hemizygous mice are protected from hyperoxic lung injury and death

Nuclear Factor I (Nfi) genes encode transcription factors essential for the development of organ systems including the lung. Nfib null mice die at birth with immature lungs. Nfib hemizygous mice have reduced lung maturation with decreased survival. We therefore hypothesized that these mice would be more sensitive to lung injury and would have lower survival to hyperoxia. Adult Nfib hemizygous mice and their wild-type (Wt) littermates were exposed to 100% O₂ for 89, 80, 72 and 66 h for survival studies with lung outcome measurements at 66 h. Nfib hemizygous and Wt controls were also studied in RA at 66 h. Cell counts and cytokines were measured in bronchoalveolar lavage (BAL); lung sections examined by histopathology; lung angiogenic and oxidative stress gene expression assessed by real-time PCR Unexpectedly, Nfib hemizygous mice (0/14-0%) had significantly lower mortality compared to Wt mice (10/22-45%) at 80 h of hyperoxia (P < 0.003). LD₅₀ was 80 h in the Wt group versus 89 h in the hemizygous group. There were no differences in BAL cell counts between the groups. Among the cytokines studied, MIP-2 was significantly lower in hemizygous mice exposed to hyperoxia. New vessel formation, edema, congestion, and alveolar hemorrhage were noted on histopathology at 72 and 80 h in wild-type mice. Nfib hemizygous lungs had significant downregulation of genes involved in redox signaling and inflammatory pathways. Adult Nfib hemizygous mice are relatively resistant to hyperoxia compared to wild-type littermates. Mechanisms contributing to this resistance are not clear; however, transcription factors such as Nfib may regulate cell survival and play a role in modulating postnatal lung development.

Prognostic significance of NFIA and NFIB in esophageal squamous carcinoma and esophagogastric junction adenocarcinoma

The nuclear factor I (NFI) family members, especially NFIA and NFIB, play essential roles in cancers. The roles of NFIA and NFIB in esophageal squamous cell carcinoma (ESCC) and esophagogastric junction adenocarcinoma (EJA) remain poorly known. This study aimed to determine the expression of NFIA and NFIB in ESCC and EJA and elucidate their prognostic significance. The expression of NFIA and NFIB was examined in 163 ESCC samples and 26 EJA samples by immunohistochemistry. The results showed that high NFIA expression correlated significantly with poor differentiation, lymph node metastasis, and advanced TNM stage in patients with ESCC. High NFIB expression only correlated with poor differentiation in patients with ESCC. Survival analysis showed that NFIA but not NFIB associated with short overall survival (OS) and disease‐free survival (DFS) of patients with ESCC. On the other hand, high NFIB expression correlated with lymph node metastasis, advanced TNM stage, and short OS and DFS in patients with EJA. Finally, multivariate analysis demonstrated that high NFIA expression was an independent prognostic factor for ESCC. Taken together, these results demonstrated that NFIA and NFIB could serve as prognostic indicators for ESCC and EJA, respectively.

Transcriptional deregulation underlying the pathogenesis of small cell lung cancer

The discovery of recurrent alterations in genes encoding transcription regulators and chromatin modifiers is one of the most important recent developments in the study of the small cell lung cancer (SCLC) genome. With advances in models and analytical methods, the field of SCLC biology has seen remarkable progress in understanding the deregulated transcription networks linked to the tumor development and malignant progression. This review will discuss recent discoveries on the roles of RB and P53 family of tumor suppressors and MYC family of oncogenes in tumor initiation and development. It will also describe the roles of lineage-specific factors in neuroendocrine (NE) cell differentiation and homeostasis and the roles of epigenetic alterations driven by changes in NFIB and chromatin modifiers in malignant progression and chemoresistance. These recent findings have led to a model of transcriptional network in which multiple pathways converge on regulatory regions of crucial genes linked to tumor development. Validation of this model and characterization of target genes will provide critical insights into the biology of SCLC and novel strategies for tumor intervention.