Changes in the Expression of Pluripotency Factor Oct-4 and Intensity of Apoptosis in the Uterus during Spontaneous and Immune-Dependent Abortions in Mice.

We studied the expression of pluripotency factor Oct-4 and the intensity of apoptosis in the uterus during spontaneous and immune abortions in mice. Increased expression of factor Bax and reduced protein Bcl-2 synthesis in cells of the decidual membrane and decreased Oct-4 expression in the myometrium and perimetrium were detected. Thus, both spontaneous and immune-dependent abortions impair the apoptosis processes in the decidua and the formation of a pool of Oct-4+ cells in the uterus. In immune-dependent abortions, the intensity of apoptosis of decidual cells was lower than in spontaneous abortion. Low expression of the transcription factor Oct-4 in the myometrium and perimetrium characterizes pregnancy failure irrespective of its mechanisms.

Limited sorafenib anticancer effects on primary cultured hepatocellular carcinoma cells with high NANOG expression.

Cancer stem cell is considered as an important cause to exacerbate the prognosis. NANOG and POU5F1 are markers for cancer stem cells. The associations between NANOG and POU5F1 expressions with the sorafenib anticancer effects in primary cultured hepatocellular carcinoma (HCC) cells were investigated. Eight primary cultured HCC parent cell lines and 13 subgroups established by flow cytometric sorting using NANOG and POU5F1 as targets were investigated with clinically achievable sorafenib plasma concentrations (5 and 10 µg/mL). Sorafenib showed obvious downregulation of RAF/MEK/ERK signaling pathways and dose-dependent anti-proliferative effects only on s003 parent cell line, which showed the lowest expression of NANOG among all tested cell lines except one downregulated NANOG with upregulated POU5F1 s020 subgroup. Sorafenib also inhibited proliferation in this s020 subgroup but promoted proliferation in its parent cell line. For the only one downregulated NANOG alone s015 subgroup, sorafenib which had no influence on its parent cell line inhibited proliferation in this subgroup. Only the above three cell lines could demonstrate sorafenib antiproliferative effects. On the contrary, sorafenib promoted proliferation in three (s003, s015, s071) out of four upregulated NANOG alone subgroups. On the other hand, Sorafenib showed diverse influence on proliferation among four upregulated POU5F1 alone subgroups. In conclusion, NANOG rather than POU5F1 expression is a critical marker for the anticancer effects of sorafenib on HCC. The sorafenib anticancer effects on HCC cells with high NANOG expression were limited. Sorafenib should be combined with other drug able to target cancer cells with high NANOG expression.

Expression of SSEA-4 and Oct-4 from somatic cells in primary mouse gastric cell culture induced by brief strong acid.

Environmental changes can stress and alter biology at the molecular and cellular level. For example, metal-protein interaction is a classic physic and biological property of nature, which is fundamentally influenced by acidity. Here, we report a unique cellular reprogramming phenomenon in that a brief strong acid treatment induced the expression of pluripotent stem cell (PSC) markers. We used strong acid to briefly challenge mix-cultured gastric cells, and then subcultured survived cells in a normal cell culture medium. We found that survival acid-treated cells expressed PSC markers detected by commonly used pluripotent antibodies such as SSEA-4 and Oct4. In addition, we observed that the survived cells from the acid challenge grew faster during the second and third weeks of subculture and had a relative short doubling time (DT) than the controls. PSC marker-labeled 'older' cells also presented immature cell-like morphology with some having marker Oct4 in the nucleus. Finally, the expression of the markers appeared to be sensitive to metal ion chelation. Removal of the metals during a brief acid treatment reduced pluripotent marker-positive cells, suggesting the dissociation of metals from metal-binding proteins may be a factor involved in the induction of stem cell markers. Our findings reveal that somatic cells appear to possess a plasticity feature to express pluripotent marker proteins or to select cell subpopulations that express pluripotent marker proteins when cells are transiently exposed to strong acid. It opens new directions for understanding conserved regulatory mechanisms involved in cellular survival under stressful stimulation.

A Comparative Assessment of Marker Expression Between Cardiomyocyte Differentiation of Human Induced Pluripotent Stem Cells and the Developing Pig Heart.

The course of differentiation of pluripotent stem cells into cardiomyocytes and the intermediate cell types are characterized using molecular markers for different stages of development. These markers have been selected primarily from studies in the mouse and from a limited number of human studies. However, it is not clear how well mouse cardiogenesis compares with human cardiogenesis at the molecular level. We tackle this issue by analyzing and comparing the expression of common cardiomyogenesis markers [platelet-derived growth factor receptor, alpha polypeptide (PDGFR-α), fetal liver kinase 1 (FLK1), ISL1, NK2 homeobox 5 (NKX2.5), cardiac troponin T (CTNT), connexin43 (CX43), and myosin heavy chain 7 (MYHC-B)] in the developing pig heart at embryonic day (E)15, E16, E18, E20, E22, and E24 and in differentiating cardiomyocytes from human induced pluripotent stem cells (hiPSCs). We found that porcine expression of the mesoderm marker FLK1 and the cardiac progenitor marker ISL1 was in line with our differentiating hiPSC and reported murine expression. The cardiac lineage marker NKX2.5 was expressed at almost all stages in the pig and hiPSC, with an earlier onset in the hiPSC compared with reported murine expression. Markers of immature cardiomyocytes, CTNT, and MYHC-B were consistently expressed throughout E16-E70 in the pig, which is comparable with mouse development, whereas the markers increased over time in the hiPSC. However, the commonly used mature cardiomyocyte marker, CX43, should be used with caution, as it was also expressed in the pig mesoderm, as well as hiPSC immature cardiomyocytes, while this has not been reported in mice. Based on our observations in the various species, we suggest to use FLK1/PDGFR-α for identifying cardiac mesoderm and ISL1/NKX2.5 for cardiac progenitors. Furthermore, a combination of two or more of the following, CTNT+/MYHC-B+/ISL1+ could mark immature cardiomyocytes and CTNT+/ISL1- mature cardiomyocytes. CX43 should be used together with sarcomeric proteins. This knowledge may help improving differentiation of hiPSC into more in vivo-like cardiac tissue in the future.

Differential expression of Oct-4, CD44, and E-cadherin in eutopic and ectopic endometrium in ovarian endometriomas and their correlations with clinicopathological variables.

BACKGROUND: Endometriosis is an estrogen-dependent inflammatory disease that often causes infertility and chronic pelvic pain. Although endometriosis is known as a benign disease, it has demonstrated characteristics of malignant neoplasms, including neoangiogenesis, tissue invasion, and cell implantation to distant organs. Octamer-binding protein 4 (Oct-4) is a molecular marker for stem cells that plays an essential role in maintaining pluripotency and self-renewal processes in various types of benign and malignant tissues. CD44 is a multifunctional cell surface adhesion molecule that acts as an integral cell membrane protein and plays a role in cell-cell and cell-matrix interactions. E-cadherin is an epithelial cell-cell adhesion molecule that plays important role in the modulation of cell polarization, cell migration, and cancer metastasis. The aim of this study was to investigate the expression patterns of Oct-4, CD44, and E-cadherin in eutopic and ectopic endometrial tissues from women with endometrioma compared to control endometrial tissues from women without endometrioma. METHODS: In the present study, Oct-4, CD44, and E-cadherin expressions were evaluated in eutopic and ectopic endometrial tissue samples from women with endometrioma (n = 32) and compared with those of control endometrial tissue samples from women without endometrioma (n = 30). RESULTS: Immunohistochemical expression of Oct-4 was significantly higher in the ectopic endometrial tissue samples of women with endometrioma than in the control endometrial tissue samples (p = 0.0002). Conversely, CD44 and E-cadherin expressions were significantly lower in the ectopic endometrial tissue samples of women with endometrioma than in the control endometrial tissue samples (p = 0.0137 and p = 0.0060, respectively). Correlation analysis demonstrated significant correlations between Oct-4 expression and endometrioma cyst diameter (p = 0.0162), rASRM stage (p = 0.0343), and total rASRM score (p = 0.0223). Moreover, CD44 expression was negatively correlated with the presence of peritoneal endometriotic lesions (p = 0.0304) while E-cadherin expression was negatively correlated with the presence of deep infiltrating endometriosis (p = 0.0445). CONCLUSIONS: Increased expression of Oct-4 and decreased expression of adhesion molecules in endometriotic tissues may contribute to the development and progression of endometriosis.

Papillary Thyroid Cancer Tumor Spheres Cultured by Passaging Without Sorting Exhibit Cancer Stemness.

AIM: Cancer stem-like cell (CSC) markers and the role of CSCs derived from papillary thyroid carcinoma (PTC) in pathogenesis are unclear. This study aimed to investigate CSC properties using tumor spheres from passaged PTC cells but without sorting CSCs. MATERIALS AND METHODS: To identify the properties of CSCs derived from PTC, the expression of SRY-box transcription factor 2(SOX2), octamer-binding transcription factor 4 (OCT4), Nanog homeobox (NANOG), thyroglobulin (TG), thyroid-stimulating hormone receptor (TSHR), E-cadherin, YES-associated protein 1 (YAP1), and signal transducer and activator of transcription 3 (STAT3) was investigated in tumor spheres serially passaged without sorting CSCs. RESULTS: The cultured tumor spheres had cancer stemness; high expression of OCT4, SOX2, NANOG, and YAP1; low expression of E-cadherin; and varied expression of TG, TSHR, and STAT3. PTC tumor spheres transfected with small interfering RNA targeting YAP1 had fewer CSC properties than the non-transfected tumor spheres did. CONCLUSION: Tumor spheres derived from PTC cells by passaging without sorting CSCs have more stem-like cell properties, and less differentiation potential. Thus, this simple and cost-effective method can be used for the enrichment of PTC stemness for employment in cell-based models, reducing the need for use of animal models.

Overexpression of the transcription factors OCT4 and KLF4 improves motor function after spinal cord injury.

INTRODUCTION: Astrogliosis and glial scar formation following spinal cord injury (SCI) are viewed as major obstacles that hinder axonal regeneration and functional recovery. Regulating the glial scar and axonal regeneration in the lesion site is important for treating SCI. AIMS: Considering the important role of astrocyte in glial scar formation and subsequent axonal regeneration, we intended to investigate the effect of the transcription factors OCT4 and KLF4 on astrocyte and the underlying mechanism after spinal cord contusion injury in transgenic mice. RESULTS: Western blotting, q-PCR, immunofluorescence, and functional evaluation suggested that glial fibrillary acidic protein (GFAP) expression decreased in the lesion area, the porosity of the scar increased, and remyelination enhanced. Mice overexpressing the transcription factors OCT4 and KLF4 had higher Basso Mouse Scale scores than did the control mice. Moreover, using immunofluorescence and Western blotting, we discovered that some astrocytes expressed nestin and sox2 protein, suggesting that these astrocytes were reprogrammed into neural stem cell-like cells. Furthermore, a cell scratch assay showed that the migration ability of the astrocytes was significantly inhibited in the presence of the transcription factors OCT4 and KLF4. In addition, we demonstrated that the Hippo/Yap pathway was activated after these two transcription factors overexpressed in astrocytes. CONCLUSIONS: In summary, these results suggest that overexpression of the transcription factors OCT4 and KLF4 could induce astrocyte reprogramming, which subsequently improves remyelination and functional recovery after SCI.

Human papillomavirus E7 binds Oct4 and regulates its activity in HPV-associated cervical cancers.

Octamer binding transcription factor-4 (Oct4), is highly expressed in stem cells and has indispensable roles in pluripotency and cellular reprogramming. In contrast to other factors used for cellular reprogramming, a role for Oct4 outside embryonic stem cells has been elusive and highly controversial. Emerging evidence implicates Oct4 in the carcinogenic process, but the mechanism through which Oct4 may be functioning in cancers is not fully appreciated. Here, we provide evidence that Oct4 is expressed in human cervical cancer and this expression correlates with the presence of the human papillomavirus (HPV) oncogenes E6 and E7. Surprisingly, the viral oncogenes can complement exogenously provided Oct4 in reprogramming assays, providing functional validation for their ability to activate Oct4 transcription in Mouse Embryonic Fibroblasts (MEFs). To interrogate potential roles of Oct4 in cervical cancers we knocked-down Oct4 in HPV(+) (HeLa & CaSki) and HPV(-) (C33A) cervical cancer cell lines and found that Oct4 knockdown attenuated clonogenesis, only in the HPV(+) cells. More unexpectedly, cell proliferation and migration, were differentially affected in HPV(+) and HPV(-) cell lines. We provide evidence that Oct4 interacts with HPV E7 specifically at the CR3 region of the E7 protein and that introduction of the HPV oncogenes in C33A cells and human immortalised keratinocytes generates Oct4-associated transcriptional and phenotypic patterns, which mimic those seen in HPV(+) cells. We propose that a physical interaction of Oct4 with E7 regulates its activity in HPV(+) cervical cancers in a manner not seen in other cancer types.

3-Hydroxyhexanoate-based polycationic nanoparticle system for delivering reprogramming factors.

Aim: In this study, we aimed to develop a polycationic non-viral carrier for the delivery of the reprogramming factors to the L929 fibroblast cell.Methods: We have prepared (3-hydroxybutyrate-co-3-hydroxyhexanoate) PHBHHx-based nanoparticles with the solvent diffusion method. Cytotoxicity of PXNs was determined via MTT assay. Transfection efficiency was evaluated via screening GFP expression by fluorescence microscopy. The expression of reprogramming factors (Oct4, Klf4, and Sox2) was determined by RT-qPCR.Results: PXNs with 32.9 ± 0.41 mV zeta potential and 177.6 ± 0.80 nm size were used for transfection of L929 Fbroblast cells. The percentage of cell viability of PXN were between 91.8%(±2.9) and 42.1%(±1.3). The transfection efficiency was found as 71.6%(±3,5). According to RT-qPCR data, the rate of transfection factors was significantly increased after the 11th cycle compared to non-transfected cells. Based on these results, it can be concluded that newly developed PXN is thought to be an effective tool for reprogramming cells.

Oct-4 Enhanced the Therapeutic Effects of Mesenchymal Stem Cell-Derived Extracellular Vesicles in Acute Kidney Injury.

BACKGROUND/AIMS: Acute kidney injury (AKI) is a common clinical condition that can lead to chronic kidney failure. Although mesenchymal stem cell-derived extracellular vesicles (MSC EVs) are regarded as a potent AKI treatment, the mechanisms underlying their beneficial effects remain unclear. Oct-4 may play an important role in tissue injury repair. We thus hypothesized that oct-4 overexpression might enhance the therapeutic effects of MSC EVs in AKI treatment. METHODS: Renal tubular epithelial cells were cultured in a low oxygen environment, then cocultured with MSC EVs or control medium for 48 h. BrdU and transferase-mediated dUTP nick-end labeling (TUNEL) staining were used to assess cell proliferation and apoptosis. Mice subjected to ischemia reperfusion were randomly divided into 4 groups, then injected with either phosphate-buffered saline (vehicle), EVs, EVs overexpressing oct-4 (EVs+Oct-4), and EVs not expressing Oct-4 (EVs-Oct-4). Blood creatinine (CREA) and urine nitrone levels were assessed 48 h and 2 weeks after injection. After ischemia reperfusion, renal tissues from each group were stained with TUNEL and proliferating cell nuclear antigen (PCNA) to determine the degree of apoptosis and proliferation. Masson trichrome staining was used to evaluate renal fibrosis progression. Snail gene expression was assessed using polymerase chain reaction (PCR). RESULTS: At 48 h after hypoxic treatment, TUNEL and BrdU staining indicated that the EVs+Oct-4 group had the least apoptosis and the most proliferation, respectively. Treatment with EVs overexpressing Oct-4 significantly decreased serum Crea and blood urea nitrogen levels and rescued kidney fibrosis, as indicated by the low proportion of Masson staining, high number of PCNA-positive cells, and low number of TUNEL-positive cells. PCR analysis indicated that Snail was most upregulated in the vehicle group and least upregulated in the EVs+Oct-4 group. CONCLUSIONS: MSC EVs had a pronounced therapeutic effect on ischemic reperfusion injury-related AKI, and Oct-4 overexpression enhanced these therapeutic effects. Our results may inspire a new direction for AKI treatment with MSC EVs.

Association of SOX2, OCT4 and WNT5A Expression in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma: An Immunohistochemical Study.

The cancer stem cells deliver uncontrolled proliferative capacity within the tumor imparting to increasing size while epithelial mesenchymal transition adds to the invasive potential. Studies using specific markers elucidating the role of these phenomena may bring advancement in the targeted therapy of tumor. SOX2 and OCT4 are two among few stem cell markers indicative of proliferative potential and WNT5A is an epithelial mesenchymal transition marker indicative of invasive potential. We aimed to determine the association between expression of SOX2, OCT4 and WNT5A in oral epithelial dysplasia, oral squamous cell carcinoma and normal oral mucosa. 20 cases of oral squamous cell carcinoma, 20 cases of oral epithelial dysplasia (leukoplakia with dysplasia) and 25 normal oral mucosa tissues specimens were immunohistochemically stained to assess SOX2, OCT4 and WNT5A expression. SOX2 expression was higher in oral squamous cell carcinoma than in oral epithelial dysplasia and very low in normal oral mucosa. OCT4 was very low in oral squamous cell carcinoma and oral epithelial dysplasia when compared to SOX2, while negative in normal tissues. Co-expression of SOX2 and OCT4 showed statistically non-significant difference for tumor proliferation. WNT5A expression was found to be increasing from normal oral mucosa to oral epithelial dysplasia and oral squamous cell carcinoma. In conformity with present study, SOX2 itself can act as a potential marker for proliferation in tumor cells while OCT4 has non-significant role in regulation of tumor behavior in oral squamous cell carcinoma as well as in oral epithelial dysplasia. WNT5A can be a putative marker in studying invasive potential of oral squamous cell carcinoma.

Role of OCT4 in cancer stem-like cells and chemotherapy resistance.

Cancer stem-like cells (CSCs) contribute to the tumorigenicity, progression, and chemoresistance of cancers. It is not known whether CSCs arise from normal stem cells or if they arise from differentiated cancer cells by acquiring self-renewal features. These CSCs share stem cell markers that normal stem cells express. There is a rising interest in octamer-binding transcription factor 4 (OCT4), one of the stem cell factors that are essential in embryogenesis and pluripotency. OCT4 is also overexpressed in CSCs of various cancers. Although the majority of the studies in CSCs reported a positive association between the expression of OCT4 and chemoresistance and an inverse correlation between OCT4 and clinical prognosis, there are studies rebuking these findings, possibly due to the sparsity of stem cells within tumors and the heterogeneity of tumors. In addition, post-translational modification of OCT4 affects its activity and warrants further investigation for its association with chemoresistance and prognosis.

Increased Expression of Gankyrin and Stemness Factor Oct-4 are Associated with Unfavorable Clinical Outcomes and Poor Benefit of Tamoxifen in Breast Carcinoma Patients.

Tamoxifen is the most important treatment component in estrogen receptor positive (ER+) breast carcinoma patients. Tamoxifen resistance incidence presents an important obstacle in clinical treatment. Mechanisms underlying tamoxifen refractory are not completely understood. Although elevated expression of Gankyrin (P28GANK) and stem cell markers Nanog, Oct-4 and Sox-2 have been reported in breast carcinoma, their role in tamoxifen resistance progression has not been explored. In the present study, P28GANK and stem cell markers Nanog, Oct-4 and Sox-2 expression were evaluated using quantitative RT-PCR and immunohistochemical technology in 72 breast carcinoma patients who received tamoxifen as adjuvant anti-hormone treatment. Expression data were correlated with the clinical outcome and survival of patients. Data analysis showed that P28GANK, Oct-4 and Sox-2 transcripts were significantly overexpressed in tamoxifen resistance patients. Immunohistochemical staining indicated that protein expression of P28GANK and Oct-4 were also significantly higher in tamoxifen resistance patients. We have shown a positive correlation between mRNA and protein expression of P28GANK, Oct-4 and Sox-2. Multivariate logistic regression analysis indicated that P28GANK (P = 0.002) and Oct-4 (P = 0.013) overexpression could be negative independent factors of disease outcome. Additionally, in the whole study group, multivariate Cox regression analysis revealed that high expression of P28GANK and Oct-4 remained significant and unfavorable predictive factors for patients' survival. These findings suggest that Gankyrin and Oct-4 overexpression could promote tamoxifen refractory in breast cancer patients. More studies are warranted to clarify the predictive role of these potential biomarkers for patients who don't benefit from tamoxifen treatment and their possible application as prognostic markers in ER+ tamoxifen-treated breast carcinoma patients.

Genetic tool for fate mapping of Oct4 (Pou5f1)-expressing cells and their progeny past the pluripotency stage.

BACKGROUND: Methods based on site-specific recombinases are widely used in studying gene activities in vivo and in vitro. In these studies, constitutively active or inducible variants of these recombinases are expressed under the control of either lineage-specific or ubiquitous promoters. However, there is a need for more advanced schemes that combine these features with possibilities to choose a time point from which lineage tracing starts in an autonomous fashion. For example, the key mammalian germline gatekeeper gene Oct4 (Pou5f1) is expressed in the peri-implantation epiblast which gives rise to all cells within embryos. Thus the above techniques are hardly applicable to Oct4 tracing past the epiblast stage, and the establishment of genetic tools addressing such a limitation is a highly relevant pursuit. METHODS: The CRISPR/Cas9 tool was used to manipulate the genome of mouse embryonic stem cells (ESCs), and various cell culture technics-to maintain and differentiate ESCs to neural cell, lentivirus-based reprogramming technique-to generate induced pluripotent stem cells (iPSCs). RESULTS: In this paper, we have developed a two-component genetic system (referred to as O4S) that allows tracing Oct4 gene activity past the epiblast stage of development. The first component represents a knock-in of an ubiquitous promoter-driven inducible Cre, serving as a stop signal for downstream tdTomato. Upon activation of Cre activity with 4-hydroxytamoxifen (4-OHT) at any given time point, the recombinase excises a stop signal and poses the second component of the system-the FlpO recombinase, knocked into 3'UTR of Oct4, to be expressed upon activation of the latter gene. Oct4-driven expression of FlpO, in turn, triggers the tdTomato expression and thus, permanently marks Oct4+ cells and their progeny. We have validated the O4S system in cultured ESCs and shown that it is capable, for example, to timely capture an activation of Oct4 gene during the reprogramming of somatic cells into iPSCs. CONCLUSIONS: The developed O4S system can be used to detect Oct4 activation event, both permanent and transient, in somatic cell types outside the germline. The approach can be equally adjusted to other genes, provided the first component of the system is placed under transcriptional control of these genes, thus, making it a valuable tool for cell fate mapping in mice.

DNMT3b/OCT4 expression confers sorafenib resistance and poor prognosis of hepatocellular carcinoma through IL-6/STAT3 regulation.

BACKGROUND: The inflammatory cytokine interleukin-6 (IL-6) is critical for the expression of octamer-binding transcription factor 4 (OCT4), which is highly associated with early tumor recurrence and poor prognosis of hepatocellular carcinomas (HCC). DNA methyltransferase (DNMT) family is closely linked with OCT4 expression and drug resistance. However, the underlying mechanism regarding the interplay between DNMTs and IL-6-induced OCT4 expression and the sorafenib resistance of HCC remains largely unclear. METHODS: HCC tissue samples were used to examine the association between DNMTs/OCT4 expression levels and clinical prognosis. Serum levels of IL-6 were detected using ELISA assays (n = 144). Gain- and loss-of-function experiments were performed in cell lines and mouse xenograft models to determine the underlying mechanism in vitro and in vivo. RESULTS: We demonstrate that levels of DNA methyltransferase 3 beta (DNMT3b) are significantly correlated with the OCT4 levels in HCC tissues (n = 144), and the OCT4 expression levels are positively associated with the serum IL-6 levels. Higher levels of IL-6, DNMT3b, or OCT4 predicted early HCC recurrence and poor prognosis. We show that IL-6/STAT3 activation increases DNMT3b/1 and OCT4 in HCC. Activated phospho-STAT3 (STAT-Y640F) significantly increased DNMT3b/OCT4, while dominant negative phospho-STAT3 (STAT-Y705F) was suppressive. Inhibiting DNMT3b with RNA interference or nanaomycin A (a selective DNMT3b inhibitor) effectively suppressed the IL-6 or STAT-Y640F-induced increase of DNMT3b-OCT4 and ALDH activity in vitro and in vivo. The fact that OCT4 regulates the DNMT1 expressions were further demonstrated either by OCT4 forced expression or DNMT1 silence. Additionally, the DNMT3b silencing reduced the OCT4 expression in sorafenib-resistant Hep3B cells with or without IL-6 treatment. Notably, targeting DNMT3b with nanaomycin A significantly increased the cell sensitivity to sorafenib, with a synergistic combination index (CI) in sorafenib-resistant Hep3B cells. CONCLUSIONS: The DNMT3b plays a critical role in the IL-6-mediated OCT4 expression and the drug sensitivity of sorafenib-resistant HCC. The p-STAT3 activation increases the DNMT3b/OCT4 which confers the tumor early recurrence and poor prognosis of HCC patients. Findings from this study highlight the significance of IL-6-DNMT3b-mediated OCT4 expressions in future therapeutic target for patients expressing cancer stemness-related properties or sorafenib resistance in HCC.

Oct4-mediated reprogramming induces embryonic-like microRNA expression signatures in human fibroblasts.

Oct4-mediated reprogramming has recently become a novel tool for the generation of various cell types from differentiated somatic cells. Although molecular mechanisms underlying this process are unknown, it is well documented that cells over-expressing Oct4 undergo transition from differentiated state into plastic state. This transition is associated with the acquisition of stem cells properties leading to epigenetically "open" state that is permissive to cell fate switch upon external stimuli. In order to contribute to our understanding of molecular mechanisms driving this process, we characterised human fibroblasts over-expressing Oct4 and performed comprehensive small-RNAseq analysis. Our analyses revealed new interesting aspects of Oct4-mediated cell plasticity induction. Cells over-expressing Oct4 lose their cell identity demonstrated by down-regulation of fibroblast-specific genes and up-regulation of epithelial genes. Interestingly, this process is associated with microRNA expression profile that is similar to microRNA profiles typically found in pluripotent stem cells. We also provide extensive network of microRNA families and clusters allowing us to precisely determine the miRNAome associated with the acquisition of Oct4-induced transient plastic state. Our data expands current knowledge of microRNA and their implications in cell fate alterations and contributing to understanding molecular mechanisms underlying it.

Leptin treatment of in vitro cultured embryos increases outgrowth rate of inner cell mass during embryonic stem cell derivation.

Leptin, a metabolic hormone, regulates the reproductive functions responding to both nutritional and body conditions. Embryonic stem cells play important roles in reproductive technology, but their derivation can be challenging. In this study, we evaluated the derivation rates of mouse embryonic stem cell (mESC) line from blastocysts developing in embryo culture media supplemented with different leptin concentrations. The results showed that addition of leptin into the embryo culture medium supported the in vitro development of mouse embryo. The mESC line derivation rates for media treated with 0, 10, 50, and 100 ng/ml of leptin were 61.24 % (54/88), 84.96 % (42/50), 81.79 % (61/76), and 85.78 % (56/67), respectively. In addition, leptin treatment of blastocysts upregulated the expression levels of the trophectoderm marker Cdx2, whereas inner cell mass markers Oct-4 and Nanog were not affected. mESC lines derived after leptin treatment demonstrated hallmarks of pluripotency, such as alkaline phosphatase activity, expression of, OCT4, NANOG, and SSEA1, as well as the ability to form embryoid bodies and well-differentiated teratomas. In conclusion, leptin has a positive effect on the derivation rate of mouse embryonic stem cell lines which may be, in part, due to its effects on the development of the trophectoderm cell lineage in the embryo.

OCT4B-190 protects against ischemic stroke by modulating GSK-3ß/HDAC6.

OCT4 is a key regulator in maintaining the pluripotency and self-renewal of embryonic stem cells (ESCs). Human OCT4 gene has three mRNA isoforms, termed OCT4A, OCT4B and OCT4B1. The 190-amino-acid protein isoform (OCT4B-190) is one of the major products of OCT4B mRNA, the biological function of which is still not well defined. Recent evidence suggests that OCT4B-190 may function in the cellular stress response. The glycogen synthase kinase-3ß (GSK-3ß) and histone deacetylase 6 (HDAC6) are also key stress modulators that play critical roles in the ischemic cascades of stroke. Hence, we here further investigated the effects of OCT4B-190 in the experimental stroke, and explored the underlying roles of GSK-3ß and HDAC6. We found that OCT4B-190 overexpression enhanced neuronal viability at 24 h after oxygen-glucose deprivation (OGD) treatment. Moreover, in male C57BL/6 mice subjected to transit middle cerebral artery occlusion (MCAO), OCT4B-190 overexpression reduced infarct volume and improved neurological function after stroke. Notably, we found spatio-temporal alterations of GSK-3ß and HDAC6 in the ischemic cortex and striatum, which were affected by adenovirus-mediated OCT4B-190 overexpression. OCT4B-190 demonstrated similar impacts on neuronal cultures in vitro, downregulating OGD-induced GSK-3ß activity and HDAC6 expression. In addition, we found that GSK-3ß and HDAC6 were co-expressed in the cytoplasm of neurons, and OCT4B-190 had an effect on interactions between GSK-3ß and HDAC6 in neuronal cultures subjected to OGD treatment. These findings suggest that OCT4B-190 exerts neuroprotection in the experimental stroke potentially by regulating actions of GSK-3ß and HDAC6 simultaneously, which may be an attractive therapeutic strategy for ischemic stroke.

The Octamer-Binding Transcription Factor 4 (OCT4) Pseudogene, POU Domain Class 5 Transcription Factor 1B (POU5F1B), is Upregulated in Cervical Cancer and Down-Regulation Inhibits Cell Proliferation and Migration and Induces Apoptosis in Cervical Cancer Cell Lines.

BACKGROUND The POU domain class 5 transcription factor 1B (POU5F1B), is a pseudogene that is homologous to octamer-binding transcription factor 4 (OCT4), and is located adjacent to the MYC gene on human chromosome 8q24. POU5F1B has been reported to be transcribed in several types of cancer, but its role in cervical cancer remains unclear. This study aimed to investigate the expression and function of POU5F1B in tissue samples of human cervical cancer and in cervical cancer cell lines in vitro. MATERIAL AND METHODS Quantitative reverse transcription polymerase chain reaction (qRT-PCR) was used to quantify POU5F1B expression in cervical cancer tissues and in SiHa, HeLa, CaSki, and C33A human cervical cancer cell lines. Functional in vitro studies included analysis of the effects of POU5F1B expression on cervical cancer cell proliferation, migration, and apoptosis using a Cell Counting Kit-8 (CCK-8) assay, cell migration assays, and flow cytometry. Luciferase activity assays, qRT-PCR, and Western blot were performed to confirm the expression of POU5F1B. RESULTS POU5F1B was significantly upregulated in cervical cancer tissues and cell lines. Interference with the expression of POU5F1B significantly inhibited cell proliferation, apoptosis, migration and invasion, and induced apoptosis in vitro. Western blot demonstrated that POU5F1B could modulate the expression of the OCT4 protein. CONCLUSIONS POU5F1B was upregulated in cervical cancer and down-regulation inhibited cell proliferation and migration and induced apoptosis in cervical cancer cell lines by modulating OCT4. Further studies are required to determine whether POU5F1B might be a diagnostic or prognostic biomarker or therapeutic target in cervical cancer.

OCT4 maintains self-renewal and reverses senescence in human hair follicle mesenchymal stem cells through the downregulation of p21 by DNA methyltransferases.

BACKGROUND: Self-renewal is dependent on an intrinsic gene regulatory network centered on OCT4 and on an atypical cell cycle G1/S transition, which is also regulated by OCT4. p21, a gene negatively associated with self-renewal and a senescence marker, is a member of the universal cyclin-dependent kinase inhibitors (CDKIs) and plays critical roles in the regulation of the G1/S transition. The expression of p21 can be regulated by OCT4-targeted DNA methyltransferases (DNMTs), which play distinct roles in gene regulation and maintaining pluripotency properties. The aim of this study was to determine the role of OCT4 in the regulation of self-renewal and senescence in human hair follicle mesenchymal stem cells (hHFMSCs) and to characterize the molecular mechanisms involved. METHODS: A lentiviral vector was used to ectopically express OCT4. The influences of OCT4 on the self-renewal and senescence of hHFMSCs were investigated. Next-generation sequencing (NGS) was performed to identify the downstream genes of OCT4 in this process. Methylation-specific PCR (MSP) analysis was performed to measure the methylation level of the p21 promoter region. p21 was overexpressed in hHFMSCsOCT4 to test its downstream effect on OCT4. The regulatory effect of OCT4 on DNMTs was examined by ChIP assay. 5-aza-dC/zebularine was used to inhibit the expression of DNMTs, and then self-renewal properties and senescence in hHFMSCs were detected. RESULTS: The overexpression of OCT4 promoted proliferation, cell cycle progression, and osteogenic differentiation capacity of hHFMSCs. The cell senescence of hHFMSCs was markedly suppressed due to the ectopic expression of OCT4. Through NGS, we identified 2466 differentially expressed genes (DEGs) between hHFMSCsOCT4 and hHFMSCsEGFP, including p21, which was downregulated. The overexpression of p21 abrogated the proliferation and osteogenic differentiation capacity of hHFMSCsOCT4 and promoted cell senescence. OCT4 enhanced the transcription of DNMT genes, leading to an elevation in the methylation of the p21 promoter. The inhibition of DNMTs reversed the OCT4-induced p21 reduction, depleted the self-renewal of hHFMSCsOCT4, and triggered cell senescence. CONCLUSIONS: OCT4 maintains the self-renewal ability of hHFMSCs and reverses senescence by suppressing the expression of p21 through the upregulation of DNMTs.