OCT4 Represses Inflammation and Cell Injury During Orchitis by Regulating CIP2A Expression
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ABSTRACT:
SUBMITTER: Zeng R
PROVIDER: S-EPMC8427512 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Nanog is a pivotal transcription factor in embryonic stem (ES) cells and is essential for maintaining the pluripotency and self-renewal of ES cells. SUMOylation has been proved to regulate several stem cell markers' function, such as Oct4 and Sox2. Nanog is strictly regulated by Oct4/Sox2 heterodimer. However, the direct effects of SUMOylation on Nanog expression remain unclear. In this study, we reported that SUMOylation repressed Nanog expression. Depletion of Sumo1 or its conjugating enzyme Ubc9 increased the expression of Nanog, while high SUMOylation reduced its expression. Interestingly, we found that SUMOylation of Oct4 and Sox2 regulated Nanog in an opposing manner. SUMOylation of Oct4 enhanced Nanog expression, while SUMOylated Sox2 inhibited its expression. Moreover, SUMOylation of Oct4 by Pias2 or Sox2 by Pias3 impaired the interaction between Oct4 and Sox2. Taken together, these results indicate that SUMOylation has a negative effect on Nanog expression and provides new insights into the mechanism of SUMO modification involved in ES cells regulation.
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Project description:Oct4 is considered a key transcription factor for pluripotent stem cell self-renewal. It binds to specific regions within target genes to regulate their expression and is downregulated upon induction of differentiation of pluripotent stem cells; however, the mechanisms that regulate the levels of human Oct4 expression remain poorly understood. Here we show that expression of human Oct4 is directly repressed by germ cell nuclear factor (GCNF), an orphan nuclear receptor, in hES cells. Knockdown of GCNF by siRNA resulted in maintenance of Oct4 expression during RA-induced hES cell differentiation. While overexpression of GCNF promoted repression of Oct4 expression in both undifferentiated and differentiated hES cells. The level of Oct4 repression was dependent on the level of GCNF expression in a dose-dependent manner. mRNA microarray analysis demonstrated that overexpression of GCNF globally regulates gene expression in undifferentiated and differentiated hES cells. Within the group of altered genes, GCNF down-regulated 36% of the genes, and up-regulated 64% in undifferentiated hES cells. In addition, GCNF also showed a regulatory gene pattern that is different from RA treatment during hES cell differentiation. These findings increase our understanding of the mechanisms that maintain hES cell pluripotency and regulate gene expression during the differentiation process.
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Project description:Radiotherapy is a mainstay for treatment of many human cancer types, including head and neck squamous cell carcinoma (HNSCC). Thereby, it is clinically very relevant to understand the mechanisms determining radioresistance. Here, we identify CIP2A as an Oct4 target gene and provide evidence that they co-operate in radioresistance. Oct4 positively regulates CIP2A expression both in testicular cancer cell lines as well as in embryonic stem cells. To expand the relevance of these findings we show that Oct4 and CIP2A are co-expressed in CD24 positive side-population of patient-derived HNSCC cell lines. Most importantly, all Oct4 positive HNSCC patient samples were CIP2A positive and this double positivity was linked to poor differentiation level, and predicted for decreased patient survival among radiotherapy treated HNSCC patients. Oct4 and CIP2A expression was also linked with increased aggressiveness and radioresistancy in HNSCC cell lines. Together we demonstrate that CIP2A is a novel Oct4 target gene in stem cells and in human cancer cell lines. Clinically these results suggest that diagnostic evaluation of HNSCC tumors for Oct4 or Oct4/CIP2A positivity might help to predict HNSCC tumor radioresistancy. These results also identify both Oct4 and CIP2A as potential targets for radiosensitation.
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Project description:Background: Accumulating evidence has revealed the importance of cancer stem cells (CSCs) in self-renewal and chemoresistance. Previous studies reported high expression of ZIC2 was closely associated with tumorigenesis and CSC traits. However, the role of ZIC2 as a crucial factor for regulating CSC properties in lung adenocarcinoma (LAC) remains elusive. Methods: RT-PCR and WB assay were employed to assess ZIC2 expression in 20 LAC tumor tissues and the matched non-cancerous tissues. The role of ZIC2 in LAC CSC were analyzed by evaluation of CSC-related markers expression and spheroid formation in vitro. Cisplatin and paclitaxel resistance capacities were evaluated by CCK8 assay, colony formation assay, and flow cytometry analysis. Subcutaneous NOD/SCID mice models were generated to assess in vivo CSC features. Results: High expression of ZIC2 was found in LAC tumor tissues and indicated a poor overall survival in LAC patients. ZIC2 upregulated an array of CSCs-related genes, including EpCAM, OCT4, SOX2, NANOG, C-Myc and Bmi-1. Knockdown of ZIC2 inhibited sphere-forming capacity and decreased cisplatin and paclitaxel resistance. However, overexpression of ZIC2 achieved opposite effects. Mechanically, ZIC2 acts upstream of OCT4 to promote its expression, resulting in enhancement of CSC traits in LAC. Conclusion: Our results demonstrated that ZIC2 was crucial for promoting CSC traits in LAC cells, and served as a potential biomarker for predicting prognosis. The ZIC2-OCT4 network will facilitate the evaluation of the potential therapeutic efficacy of chemotherapy and predict patient sensitivity to treatment.
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Project description:The Notch signaling pathway is a key regulator of stem cells during development, and its deregulated activity is linked to developmental defects and cancer. Transcriptional activation of Notch target genes requires cleavage of the Notch receptor in response to ligand binding, production of the Notch intracellular domain (NICD1), NICD1 migration into the nucleus, and assembly of a transcriptional complex. Post-translational modifications of Notch regulate its trafficking, turnover, and transcriptional activity. Here, we show that NICD1 is modified by small ubiquitin-like modifier (SUMO) in a stress-inducible manner. Sumoylation occurs in the nucleus where NICD1 is sumoylated in the RBPJ-associated molecule (RAM) domain. Although stress and sumoylation enhance nuclear localization of NICD1, its transcriptional activity is attenuated. Molecular modeling indicates that sumoylation can occur within the DNA-bound ternary transcriptional complex, consisting of NICD1, the transcription factor Suppressor of Hairless (CSL), and the co-activator Mastermind-like (MAML) without its disruption. Mechanistically, sumoylation of NICD1 facilitates the recruitment of histone deacetylase 4 (HDAC4) to the Notch transcriptional complex to suppress Notch target gene expression. Stress-induced sumoylation decreases the NICD1-mediated induction of Notch target genes, which was abrogated by expressing a sumoylation-defected mutant in cells and in the developing central nervous system of the chick in vivo. Our findings of the stress-inducible sumoylation of NICD1 reveal a novel context-dependent regulatory mechanism of Notch target gene expression.
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Project description:Myc proteins control cell proliferation, cell cycle progression, and apoptosis, and play important roles in cancer as well in establishment of pluripotency. Here we investigated the control of myc gene expression by the Pou5f1/Oct4 pluripotency factor in the early zebrafish embryo. We analyzed the expression of all known zebrafish Myc family members, myca, mycb, mych, mycl1a, mycl1b, and mycn, by whole mount in situ hybridization during blastula and gastrula stages in wildtype and maternal plus zygotic pou5f1 mutant (MZspg) embryos, as well as by quantitative PCR and in time series microarray data. We found that the broad blastula and gastrula stage mych expression, as well as late gastrula stage mycl1b expression, both depend on Pou5f1 activity. We analyzed ChIP-Seq data and found that both Pou5f1 and Sox2 bind to mych and mycl1b control regions. The regulation of mych by Pou5f1 appears to be direct transcriptional activation, as overexpression of a Pou5f1 activator fusion protein in MZspg embryos induced strong mych expression even when translation of zygotically expressed mRNAs was suppressed. We further showed that MZspg embryos develop enhanced apoptosis already during early gastrula stages, when apoptosis was not be detected in wildtype embryos. However, Mych knockdown alone did not induce early apoptosis, suggesting potentially redundant action of several early expressed myc genes, or combination of several pathways affected in MZspg. Experimental mych overexpression in MZspg embryos did significantly, but not completely suppress the apoptosis phenotype. Similarly, p53 knockdown only partially suppressed apoptosis in MZspg gastrula embryos. However, combined knockdown of p53 and overexpression of Mych completely rescued the MZspg apoptosis phenotype. These results reveal that Mych has anti-apoptotic activity in the early zebrafish embryo, and that p53-dependent and Myc pathways are likely to act in parallel to control apoptosis at these stages.
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Project description:Metformin, a Type II diabetic treatment drug, which inhibits transcription of gluconeogenesis genes, has recently been shown to lower the risk of some diabetes-related tumors, including breast cancer. Recently, "cancer stem cells" have been demonstrated to sustain the growth of tumors and are resistant to therapy. To test the hypothesis that metformin might be reducing the risk to breast cancers, the human breast carcinoma cell line, MCF-7, grown in 3-dimensional mammospheres which represent human breast cancer stem cell population, were treated with various known and suspected breast cancer chemicals with and without non-cytotoxic concentrations of metformin. Using OCT4 expression as a marker for the cancer stem cells, the number and size were measured in these cells. Results demonstrated that TCDD (100 nM) and bisphenol A (10 µM) increased the number and size of the mammospheres, as did estrogen (10 nM E2). By monitoring a cancer stem cell marker, OCT4, the stimulation by these chemicals was correlated with the increased expression of OCT4. On the other hand, metformin at 1 and 10 mM concentration dramatically reduced the size and number of mammospheres. Results also demonstrated the metformin reduced the expression of OCT4 in E2 & TCDD mammospheres but not in the bisphenol A mammospheres, suggesting different mechanisms of action of the bisphenol A on human breast carcinoma cells. In addition, these results support the use of 3-dimensional human breast cancer stem cells as a means to screen for potential human breast tumor promoters and breast chemopreventive and chemotherapeutic agents.
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Project description:The activation of endogenous Oct4 transcription is a key step in the reprogramming of somatic cells into induced pluripotent stem (iPS) cells but until now it has been difficult to analyze this critical event in the reprogramming process. We have generated a transgenic mouse that expresses the tamoxifen-inducible Cre recombinase MerCreMer under the control of the endogenous Oct4 locus, enabling lineage tracing of Oct4 expression in cells in vivo or in vitro, during either reprogramming or differentiation. Using this novel resource, we have determined the timing and outcome of endogenous Oct4 induction during fibroblast reprogramming. We show that both the initiation of this key reprogramming step and the ability of cells activating endogenous Oct4 expression to complete reprogramming are not influenced by the presence of exogenous c-Myc, although the overall efficiency of the process is increased by c-Myc. Oct4 lineage tracing reveals that new reprogramming events continue to initiate over a period of 3 weeks. Furthermore, the analysis of mixed colonies, where only a subset of daughter cells induce endogenous Oct4 expression, indicates the role of unknown, stochastic events in the progression of reprogramming from the initial events to a pluripotent state. Our transgenic mouse model and cells derived from it provide powerful and precise new tools for the study of iPS cell reprogramming mechanisms and have wider implications for the investigation of the role of Oct4 during development.
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Project description:We describe the internal organization of murine embryoid bodies (EBs) in terms of the structures and cell types formed as Oct4 expression becomes progressively lost. This is done by making the EBs from iPS cells carrying a novel Oct4 reporter (Oct4-MerCreMer;mTmG) which is inducible, sensitive, and permanent in all cellular progeny. When these EBs are treated with tamoxifen, the Oct4 expressing cells switch from a red to a green fluorescence color, and this is maintained thereafter by all their progeny. We show that there is no specific pattern in which Oct4 is downregulated, rather it appears to be spatially random. Many of the earliest cells to lose Oct4 expression stain positive for markers of visceral endoderm (DAB2, ?-fetoprotein (AFP), HNF4). These are randomly located, although if endoderm differentiation is allowed to commence before EB formation then an external layer is formed. This is true both of EBs made from the reporter iPS cells, or from an embryo-derived mouse ES line (R1 cells). Markers of the early body axis, Brachyury (BRA) and FOXA2, usually showed a concentration of positive cells in one region of the EB, but the morphology is not predictable and there are also scattered cells expressing these markers. These patterns are similar in R1 cells. Use of the Oct4 reporter showed a difference between BRA and FOXA2. BRA, which marks the early mesoderm, node and notochord, arises in Oct4 expressing cells on days 3-4. FOXA2, which marks the floor plate of the neural tube and definitive endoderm, as well as the node and notochord, arises at the same time but mostly in cells that have already lost Oct4 expression. Several clumps of cardiomyocytes are visible by days 7-8 of EB development, both in our iPS cells and in R1 cells. Using the Oct4 reporter we show that the cells forming these clumps lose Oct4 expression between days 3 and 5. Overall, our results indicate that EBs recapitulate normal development quite well in terms of the tempo of events and the appearance of specific markers, but they do not resemble embryos in terms of their morphology.
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