NANOG gene expression is regulated by the ETS transcription factor ETV4 in human embryonic carcinoma NCCIT cells

Comprehensive Analysis of Gene Expression Profiling to Explore Predictive Markers for Eradication Therapy Efficacy against Helicobacter pylori-Negative Gastric MALT Lymphoma

Although radiotherapy is the standard treatment for Helicobacter pylori (Hp)-negative gastric mucosa-associated lymphoid tissue (MALT) lymphoma, eradication therapy using antibiotics and an acid secretion suppressor can sometimes induce complete remission. We explored predictive markers for the response to eradication therapy for gastric MALT lymphoma that were negative for both API2-MALT1 and Hp infection using comprehensive RNA sequence analysis. Among 164 gastric MALT lymphoma patients who underwent eradication therapy as primary treatment, 36 were negative for both the API2-MALT1 fusion gene and Hp infection. Based on eradication therapy efficacy, two groups were established: complete response (CR) and no change (NC). The Kyoto Encyclopedia of Genes and Genomes pathway analysis showed that cancer-related genes and infection-related genes were highly expressed in the NC and CR groups, respectively. Based on this finding and transcription factor, gene ontology enrichment, and protein-protein interaction analyses, we selected 16 candidate genes for predicting eradication therapy efficacy. Real-time PCR validation in 36 Hp-negative patients showed significantly higher expression of olfactomedin-4 (OLFM4) and the Nanog homeobox (NANOG) in the CR and NC groups, respectively. OLFM4 and NANOG could be positive and negative predictive markers, respectively, for eradication therapy efficacy against gastric MALT lymphoma that is negative for both API2-MALT1 and Hp infection.

Harnessing a Feasible and Versatile ex vivo Calvarial Suture 2-D Culture System to Study Suture Biology

As a basic science, craniofacial research embraces multiple facets spanning from molecular regulation of craniofacial development, cell biology/signaling and ultimately translational craniofacial biology. Calvarial sutures coordinate development of the skull, and the premature fusion of one or more, leads to craniosynostosis. Animal models provide significant contributions toward craniofacial biology and clinical/surgical treatments of patients with craniofacial disorders. Studies employing mouse models are costly and time consuming for housing/breeding. Herein, we present the establishment of a calvarial suture explant 2-D culture method that has been proven to be a reliable system showing fidelity with the in vivo harvesting procedure to isolate high yields of skeletal stem/progenitor cells from small number of mice. Moreover, this method allows the opportunity to phenocopying models of craniosynostosis and in vitro tamoxifen-induction of ActincreERT2;R26Rainbow suture explants to trace clonal expansion. This versatile method tackles needs of large number of mice to perform calvarial suture research.

E26 transformation-specific variant 4 as a tumor promotor in human cancers through specific molecular mechanisms

E26 transformation-specific (ETS) variant 4 (ETV4) is an important transcription factor that belongs to the ETS transcription factor family and is essential for much cellular physiology. Recent evidence has revealed that ETV4 is aberrantly expressed in many types of tumors, and its overexpression is related to poor prognosis of cancer patients. Additionally, increasing studies have identified that ETV4 promotes cancer growth, invasion, metastasis, and drug resistance. Mechanistically, the level of ETV4 is regulated by some post-translation modulations in a broad spectrum of cancers. However, little progress has been made to comprehensively summarize the critical roles of ETV4 in different human cancers. Hence, this review mainly focuses on the physiological functions of ETV4 in various human tumors. In addition, the molecular mechanisms of ETV4-mediated cancer progression were elucidated, including how ETV4 modulates its downstream signaling pathways and how ETV4 is regulated by some factors. On this basis, the present review may provide a valuable therapeutics strategy for future cancer treatment by targeting ETV4-related pathways.

Epithelium-specific ETS transcription factor-1 regulates NANOG expression and inhibits NANOG-induced proliferation of human embryonic carcinoma cells

The epithelium-specific ETS transcription factor-1 (ESE-1) plays multiple roles in pathogenesis and normal development of epithelial tissues. NANOG, a key mediator of stem cell self-renewal and pluripotency, is also expressed in various cancers and pluripotent cells. In this study, we investigated how ESE-1 influences NANOG expression and NANOG-induced proliferation in human germ cell-derived embryonic carcinoma NCCIT cells. Endogenous ESE-1 expression in NCCIT cells significantly increased during differentiation, whereas NANOG expression decreased. In addition, NANOG expression was downregulated by exogenous overexpression of ESE-1, and increased by shRNA-mediated knockdown of ESE-1. NANOG transcriptional activity was reduced by dose-dependent ESE-1 overexpression and a putative ESE-1 binding site (EBS) was mapped within conserved region 2. Site-directed mutagenesis of the putative EBS abrogated the repressive effect of ESE-1 on NANOG promoter activity. ESE-1 directly interacted with the putative EBS to regulate transcriptional activity of NANOG. Furthermore, NANOG-induced proliferation and colony formation of NCCIT cells were inhibited by ESE-1 overexpression and stimulated by ESE-1 shRNA-mediated knockdown. Altogether, our results suggest that ESE-1 exerts an anti-proliferative effect on NCCIT cells by acting as a novel transcriptional repressor of NANOG.

ETS-Domain Transcription Factor Elk-1 Regulates Stemness Genes in Brain Tumors and CD133+ BrainTumor-Initiating Cells

Elk-1, a member of the ternary complex factors (TCFs) within the ETS (E26 transformation-specific) domain superfamily, is a transcription factor implicated in neuroprotection, neurodegeneration, and brain tumor proliferation. Except for known targets, c-fos and egr-1, few targets of Elk-1 have been identified. Interestingly, SMN, SOD1, and PSEN1 promoters were shown to be regulated by Elk-1. On the other hand, Elk-1 was shown to regulate the CD133 gene, which is highly expressed in brain-tumor-initiating cells (BTICs) and used as a marker for separating this cancer stem cell population. In this study, we have carried out microarray analysis in SH-SY5Y cells overexpressing Elk-1-VP16, which has revealed a large number of genes significantly regulated by Elk-1 that function in nervous system development, embryonic development, pluripotency, apoptosis, survival, and proliferation. Among these, we have shown that genes related to pluripotency, such as Sox2, Nanog, and Oct4, were indeed regulated by Elk-1, and in the context of brain tumors, we further showed that Elk-1 overexpression in CD133+ BTIC population results in the upregulation of these genes. When Elk-1 expression is silenced, the expression of these stemness genes is decreased. We propose that Elk-1 is a transcription factor upstream of these genes, regulating the self-renewal of CD133+ BTICs.

Fli-1 promotes proliferation and upregulates NANOGP8 expression in T-lymphocyte leukemia cells

Friend leukemia integration 1 (Fli-1) is a member of the E26 transformation-specific (ETS) transcription factor family. Fli-1 regulates normal hematopoiesis and vasculogenesis, and its aberrant expression underlies virus-induced leukemias and various types of human cancers. NANOGP8, a retro-pseudogene of stem cell mediator NANOG, is expressed predominantly in cancer cells and plays a role in tumorigenesis. In this study, we demonstrate that Fli-1 expression enhances human acute T-cell leukemia Jurkat cell proliferation and that Fli-1 acts as a transcriptional activator of NANOGP8 expression in these cells. NANOGP8 and Fli-1 are highly expressed in Jurkat cells, whereas NANOG was undetectable at both the RNA and protein levels. Moreover, the expression of endogenous NANOGP8 was significantly influenced by gain of function and loss of function of Fli-1. Promoter-reporter assays showed that NANOGP8 transcription was significantly upregulated by dose-dependent Fli-1 overexpression. A series of deletion mutagenesis of NANOGP8 promoter sequence revealed that NANOGP8 promoter activity was tightly regulated and found the minimal promoter region sufficient to activate NANOGP8 transcription mediated by Fli-1. Moreover, site-directed mutagenesis of the putative binding site abolished both NANOGP8 full-length and minimal promoter activities. Binding assays revealed that Fli-1 directly interacts with the potent binding site in NANOG promoter region. Taken together, our data demonstrate that Fli-1 is a novel upstream transcriptional activator of NANOGP8 and provide the molecular details of Fli-1-mediated NANOGP8 gene expression. Ultimately, these findings may contribute to understanding the expanded regulatory mechanisms of oncogenic NANOGP8 and ETS family transcription factors in leukemogenesis.

The expression of the embryonic gene Cripto-1 is regulated by OCT4 in human embryonal carcinoma NCCIT cells

Cripto-1 and OCT4, expressed in stem cells and cancers, play important roles in tumorigenesis. Here, we demonstrate that Cripto-1 expression is regulated by OCT4 in human embryonic carcinoma NCCIT cells. The endogenous expression of Cripto-1 and OCT4 is significantly reduced during differentiation. Cripto-1 expression is increased by OCT4 overexpression, but decreased by shRNA-mediated OCT4 knockdown. OCT4 overexpression significantly activates Cripto-1 transcriptional activity. A 5'-upstream minimal promoter sequence in the gene-encoding Cripto-1 is significantly activated by OCT4 overexpression. Mutation of the putative OCT4-binding site abolishes OCT4-mediated activation of the Cripto-1 promoter. The OCT4 transactivation domains mediate transcriptional activity of the Cripto-1 minimal promoter through direct interaction. Taken together, OCT4 plays an important role as a transcriptional activator of Cripto-1 expression in NCCIT cells.

Novel functionalized nanoparticles for tumor-targeting co-delivery of doxorubicin and siRNA to enhance cancer therapy

Human homeobox protein (Nanog) is highly expressed in most cancer cells and has gradually emerged as an excellent target in cancer therapy, owing to its regulation of cancer cell proliferation, metastasis and apoptosis. In this study, we prepared tumor-targeting functionalized selenium nanoparticles (RGDfC-SeNPs) to load chemotherapeutic doxorubicin (DOX) and Nanog siRNA. Herein, RGDfC peptide was used as a tumor-targeting moiety which could specifically bind to αvβ3 integrins overexpressed on various cancer cells. The sizes of RGDfC-SeNPs@DOX nanoparticles (~12 nm) were confirmed by both dynamic light scattering and transmission electron microscopy. The chemical structure of RGDfC-SeNPs@DOX was characterized via Fourier-transform infrared spectroscopy. The RGDfC-SeNPs@DOX was compacted with siRNA (anti-Nanog) by electrostatic interaction to fabricate the RGDfC-SeNPs@DOX/siRNA complex. The RGDfC-SeNPs@DOX/siRNA complex nanoparticles could efficiently enter into HepG2 cells via clathrin-associated endocytosis, and showed high gene transfection efficiency that resulted in enhanced gene silencing. The in vivo biodistribution experiment indicated that RGDfC-SeNPs@DOX/siRNA nanoparticles were capable of specifically accumulating in the tumor site. Furthermore, treatment with RGDfC-SeNPs@DOX/siRNA resulted in a more significant anticancer activity than the free DOX, RGDfC-SeNPs@DOX or RGDfC-SeNPs/siRNA in vitro and in vivo. In summary, this study shows a novel type of DOX and siRNA co-delivery system, thereby providing an alternative route for cancer treatment.