Colorectal cancer (CRC) is the third most common cancer in the world known for its poor recurrence-free prognosis. Previous studies have shown that it is closely linked with cancer stem cells (CSCs), ...which have self-renewal potential and the capacity to differentiate into diverse populations. Nanog is an important transcription factor that functions to maintain the self-renewal and proliferation of embryonic stem cells; however, many recent studies have shown that Nanog is also highly expressed in many cancer stem cells. To investigate whether Nanog plays a crucial role in maintaining the stemness of colorectal CSCs, RNA interference was used to downregulate Nanog expression in the CRC stem cell line, EpCAM+CD44+HCT-116 cells (CCSCs). We examined the anti-tumor function of Nanog in vitro and in vivo, using small interfering RNA. Our results revealed that the Nanog mRNA expression level in CCSCs was higher than that in HCT-116 cells. We found that the depletion of Nanog inhibited proliferation and promoted apoptosis in CCSCs. In addition, the invasive ability of CCSCs was markedly restricted when Nanog was silenced by small interfering RNA. Furthermore, we found that the silencing of Nanog decreased tumor size and weight and improved the survival rate of tumor-bearing mice. In conclusion, these findings collectively demonstrate that Nanog, which is highly expressed in CRC stem cells, is a key factor in the development of tumor growth, and it may serve as a potential marker of prognosis and a novel and effective therapeutic target for the treatment of CRC.
•Cancer stem cells are primarily implicated in tumor initiation, progression, metastasis, and relapse after therapy.•Nanog plays the key role of tumor growth in colon cancer stem cells (CCSCs).•Silencing of Nanog expression suppressed the proliferation, invasion, and induced of apoptosis of CCSCs in vitro.•Nanog siRNA treatment inhibited tumor growth and improves survival in vivo.
Autophagy is required for benign hepatic tumors to progress into malignant hepatocellular carcinoma. However, the mechanism is unclear. Here, we report that mitophagy, the selective removal of ...mitochondria by autophagy, positively regulates hepatic cancer stem cells (CSCs) by suppressing the tumor suppressor p53. When mitophagy is enhanced, p53 co-localizes with mitochondria and is removed by a mitophagy-dependent manner. However, when mitophagy is inhibited, p53 is phosphorylated at serine-392 by PINK1, a kinase associated with mitophagy, on mitochondria and translocated into the nucleus, where it binds to the NANOG promoter to prevent OCT4 and SOX2 transcription factors from activating the expression of NANOG, a transcription factor critical for maintaining the stemness and the self-renewal ability of CSCs, resulting in the reduction of hepatic CSC populations. These results demonstrate that mitophagy controls the activities of p53 to maintain hepatic CSCs and provide an explanation as to why autophagy is required to promote hepatocarcinogenesis.
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•Autophagy positively regulates hepatic cancer stem cells via the suppression of p53•p53 downregulates NANOG and is removed with mitochondria by mitophagy•PINK1 binds to p53 on mitochondria and phosphorylates p53 at serine-392•PINK1-activated p53 is localized to the nucleus when mitophagy is impaired
Autophagy is required for the malignant transformation of liver tumors. Liu et al. demonstrated that mitophagy, the selective removal of mitochondria by autophagy, was required to maintain the hepatic cancer stem cell population by removing mitochondria-associated p53, which otherwise would be activated by PINK1 to suppress the expression of NANOG.
Emerging evidence have illustrated the vital role of long noncoding RNAs (lncRNAs) long intergenic non-protein coding RNA 00511 (LINC00511) on the human cancer progression and tumorigenesis. However, ...the role of LINC00511 in breast cancer tumourigenesis is still unknown. This research puts emphasis on the function of LINC00511 on the breast cancer tumourigenesis and stemness, and investigates the in-depth mechanism.
The lncRNA and RNA expression were measured using RT-PCR. Protein levels were measured using western blotting analysis. CCK-8, colony formation assays and transwell assay were performed to evaluate the cell proliferation ability and invasion. Sphere-formation assay was also performed for the stemness. Bioinformatic analysis, chromatin immunoprecipitation (ChIP) and luciferase reporter assays were carried to confirm the molecular binding.
LINC00511 was measured to be highly expressed in the breast cancer specimens and the high-expression was correlated with the poor prognosis. Functionally, the gain and loss-of-functional experiments revealed that LINC00511 promoted the proliferation, sphere-formation ability, stem factors (Oct4, Nanog, SOX2) expression and tumor growth in breast cancer cells. Mechanically, LINC00511 functioned as competing endogenous RNA (ceRNA) for miR-185-3p to positively recover E2F1 protein. Furthermore, transcription factor E2F1 bind with the promoter region of Nanog gene to promote it transcription.
In conclusion, our data concludes that LINC00511/miR-185-3p/E2F1/Nanog axis facilitates the breast cancer stemness and tumorigenesis, providing a vital insight for them.
Antimicrobial triclosan (TCS), one of the popular ingredients added to sanitizing products, has widespread use in personal care. However, it poses potential risks to reproduction and development. ...Unfortunately, the underlying mechanisms remain largely unclear. This study aimed to investigate effects of TCS on the development of preimplantation mouse embryo and explore related mechanisms Mouse zygotes were collected and cultured to blastocysts in KSOM medium supplemented with four different concentrations of TCS. The development rates, pluripotency or stem cells markers, and microRNA (miR)− 134 were compared between control and experimental groups across each specific developmental stage. Prolonged exposure to TCS remarkably impaired early embryo development in vitro by hampering morula and blastocyst formations (P < 0.05, P < 0.001). The arrest of embryo development was linked with decreased expressions of pluripotency or stem cells markers, especially Nanog and Notch1. Moreover, based on miRWalk database and in vitro luciferase assays, we confirmed that miR-134 induced by TCS was a negative regulator of Nanog. Crucially, impaired TCS-treated embryos could be rescued by inhibiting miR-134 or forced overexpressing Nanog mRNA. Altogether, our results highlight that pathologically relevant level of TCS compromises preimplantation mouse embryo development by inducing miR-134 and triggering miR-134/Nanog axis. Considering high conservative of miR-134 between human and mouse, it should be the most promising potential target to regulate development of preimplantation embryo.
•Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development.•Nanog, as a transcription factor, is one of the most critical markers in CSCs.•Nanog ...regulates multiple malignant phenotypes by modulating multiple signaling pathways, including AKT, STAT3 and P53 pathways.•Targeting Nang by miRNA may be effective approach in cancer treatment.
Cancer stem cells (CSCs) are a small population of malignant cells that induce tumor onset and development. CSCs share similar features with normal stem cells in the case of self-renewal and differentiation. They also contribute to chemoresistance and metastasis of cancer cells, leading to therapeutic failure. To identify CSCs, multiple cell surface markers have been characterized, including Nanog, which is found at high levels in different cancers. Recent studies have revealed that Nanog upregulation has a substantial association with the advanced stages and poor prognosis of malignancies, playing a pivotal role through tumorigenesis of multiple human cancers, including leukemia, liver, colorectal, prostate, ovarian, lung, head and neck, brain, pancreatic, gastric and breast cancers. Nanog through different signaling pathways, like JAK/STAT and Wnt/β-catenin pathways, induces stemness, self-renewal, metastasis, invasiveness, and chemoresistance of cancer cells. Some of these signaling pathways are common in various types of cancers, but some have been found in one or two cancers. Therefore, this review aimed to focus on the function of Nanog in multiple cancers based on recent studies surveying the suitable approaches to target Nanog and inhibit CSCs residing in tumors to gain favorable results from cancer treatments.
The self‐renewal efficiency of mouse embryonic stem cells (ESCs) is determined by the concentration of the transcription factor NANOG. While NANOG binds thousands of sites in chromatin, the ...regulatory systems that control DNA binding are poorly characterised. Here, we show that NANOG is phosphorylated by casein kinase I, and identify target residues. Phosphomimetic substitutions at phosphorylation sites within the homeodomain (S130 and S131) have site‐specific functional effects. Phosphomimetic substitution of S130 abolishes DNA binding by NANOG and eliminates LIF‐independent self‐renewal. In contrast, phosphomimetic substitution of S131 enhances LIF‐independent self‐renewal, without influencing DNA binding. Modelling the DNA–homeodomain complex explains the disparate effects of these phosphomimetic substitutions. These results indicate how phosphorylation may influence NANOG homeodomain interactions that underpin ESC self‐renewal.
Background
OCT4, SOX2, and NANOG are major transcription factors related to stem cell self‐renewal and differentiation. The aim of this study was to examine the association of OCT4, SOX2, and NANOG ...expression levels with the development and prognosis of patients with oral squamous cell carcinoma (OSCC).
Materials and Methods
Expression levels of OCT4, SOX2, and NANOG were evaluated by immunohistochemistry with tissue microarray slides of 436 OSCC, 362 corresponding tumor‐adjacent normal (CTAN) tissues, and 71 normal uvula epithelium tissues. The clinicopathologic and follow‐up data of the OSCC patients were recorded.
Results
OCT4 expression was significantly higher in normal and CTAN tissues than in tumor tissue (both P < 0.001). SOX2 expression in CTAN tissue was significantly higher than that in normal (P = 0.021) and tumor tissues (P < 0.001). However, NANOG expression was significantly higher in CTAN (P = 0.014) and tumor tissues (P = 0.009) than in normal tissue. Higher OCT4 and SOX2 expressions were associated with earlier AJCC stage (P = 0.002 and P < 0.001), small tumor size (P = 0.017 and P = 0.001), and the absence of lymph node metastasis (P = 0.015 and P = 0.025). Higher levels of SOX2 expression were associated with better disease‐specific survival (P = 0.002) even after adjustment for clinicopathologic factors.
Discussion
OCT4 and SOX2 are biomarkers of tumorigenesis and early stage OSCC. SOX2 is an independent prognostic factor for OSCC.
NANOG is an important stem cell transcription factor involved in human development and cancerogenesis. Its expression is complex and regulated on different levels. Moreover, NANOG protein might ...regulate hundreds of target genes at the same time. NANOG is crucial for preimplantation development phase and progressively decreases during embryonic stem cells differentiation, thus regulating embryonic and fetal development. Postnatally, NANOG is undetectable or expressed in very low amounts in the majority of human tissues. NANOG re-expression can be detected during cancerogenesis, already in precancerous lesions, with increasing levels of NANOG in high grade dysplasia. NANOG is believed to enable cancer cells to obtain stem-cell like properties, which are believed to be the source of expanding growth, tumor maintenance, metastasis formation, and tumor relapse. High NANOG expression in cancer is frequently associated with advanced stage, poor differentiation, worse overall survival, and resistance to treatment, and is therefore a promising prognostic and predictive marker. We summarize the current knowledge on the role of NANOG in cancerogenesis and development, including our own experience. We provide a critical overview of NANOG as a prognostic and diagnostic factor, including problems regarding its regulation and detection.
Impact statement
NANOG has emerged as a key stem cell transcription factor in normal development and cancerogenesis. It is generally regarded as a good prognostic and predictive factor in various human cancers. It is less known that it is expressed already at precancerous stages in various organs, suggesting that finally an ideal candidate diagnostic marker has been discovered, enabling to distinguish between true dysplasia and reactive atypia. NANOG regulation is complex, and new insights into our understanding of its regulation might provide important information for future development in a broad field of two entirely different processes, i.e. normal development and cancerogenesis, showing how a physiologic mechanism can be used and abused, transforming itself into a key mechanism of disease development and progression.
The localization of transcriptional activity in specialized transcription bodies is a hallmark of gene expression in eukaryotic cells.1–3 How proteins of the transcriptional machinery come together ...to form such bodies, however, is unclear. Here, we take advantage of two large, isolated, and long-lived transcription bodies that reproducibly form during early zebrafish embryogenesis to characterize the dynamics of transcription body formation. Once formed, these transcription bodies are enriched for initiating and elongating RNA polymerase II, as well as the transcription factors Nanog and Sox19b. Analyzing the events leading up to transcription, we find that Nanog and Sox19b cluster prior to transcription. The clustering of transcription factors is sequential; Nanog clusters first, and this is required for the clustering of Sox19b and the initiation of transcription. Mutant analysis revealed that both the DNA-binding domain as well as one of the two intrinsically disordered regions of Nanog are required to organize the two bodies of transcriptional activity. Taken together, our data suggest that the clustering of transcription factors dictates the formation of transcription bodies.
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•Transcription factors cluster prior to transcription•Transcriptional activity results in the disassembly of transcription factor clusters•Nanog can recruit Sox19b as well as RNA polymerase II into transcription bodies•This organizing activity of Nanog requires its DBD as well as one of its IDRs
The localization of transcriptional activity in specialized transcription bodies is a hallmark of gene expression in eukaryotic cells. Here, Kuznetsova et al. show that the transcription factor Nanog can recruit other components of the transcriptional machinery to form such transcription bodies.
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