Helicobacter pylori infection induces POU5F1 upregulation and SPP1 activation to promote chemoresistance and T cell inactivation in gastric cancer cells

Infection with Helicobacter pylori (H. pylori or Hp) is associated with an increased susceptibility to gastric diseases, notably gastric cancer (GC). This study investigates the impact of Hp infection on chemoresistance and immune activity in GC cells. Hp infection in AGS and MKN-74 cells promoted proliferation, migration and invasion, apoptosis resistance, and tumorigenic activity of cells under cisplatin (DDP) plus gemcitabine (GEM) treatment. Additionally, it dampened activity of the co-cultured CD8+ T cells. Hp infection increased POU class 5 homeobox 1 (POU5F1) level, which further activated secreted phosphoprotein 1 (SPP1) transcription to increase its expression. Silencing of either SPP1 or POU5F1 enhanced the GEM sensitivity in GC cells, and it increased the populations of CD8+ T cells and the secretion of immune-active cytokines both in vitro and in xenograft tumors in immunocompetent mice. However, the effects of POU5F1 silencing were counteracted by SPP1 overexpression. Furthermore, the POU5F1/SPP1 axis activated the PI3K/AKT signaling pathway. This study demonstrates that Hp infection induces POU5F1 upregulation and SPP1 activation, leading to increased DDP/GEM resistance and T cell inactivation in GC cells.

Optimising Electroporation Condition for CRISPR/Cas-Mediated Knockout in Zona-Intact Buffalo Zygotes

Somatic cell nuclear transfer or cytoplasm microinjection has widely been used to produce genome-edited farm animals; however, these methods have several drawbacks which reduce their efficiency. In the present study, we describe an easy adaptable approach for the introduction of mutations using CRISPR-Cas9 electroporation of zygote (CRISPR-EP) in buffalo. The goal of the study was to determine the optimal conditions for an experimental method in which the CRISPR/Cas9 system is introduced into in vitro-produced buffalo zygotes by electroporation. Electroporation was performed using different combinations of voltage, pulse and time, and we observed that the electroporation in buffalo zygote at 20 V/mm, 5 pulses, 3 msec at 10 h post insemination (hpi) resulted in increased membrane permeability and higher knockout efficiency without altering embryonic developmental potential. Using the above parameters, we targeted buffalo POU5F1 gene as a proof of concept and found no variations in embryonic developmental competence at cleavage or blastocyst formation rate between control, POU5F1-KO, and electroporated control (EC) embryos. To elucidate the effect of POU5F1-KO on other pluripotent genes, we determined the relative expression of SOX2, NANOG, and GATA2 in the control (POU5F1 intact) and POU5F1-KO-confirmed blastocyst. POU5F1-KO significantly (p ≤ 0.05) altered the expression of SOX2, NANOG, and GATA2 in blastocyst stage embryos. In conclusion, we standardized an easy and straightforward protocol CRISPR-EP method that could be served as a useful method for studying the functional genomics of buffalo embryos.

Combined Exogenous Activation of Bovine Oocytes: Effects on Maturation-Promoting Factor, Mitogen-Activated Protein Kinases, and Embryonic Competence

Oocyte activation via dual inhibition of protein synthesis and phosphorylation has improved in vitro embryo production in different mammalian species. In this study, we evaluated the effects of the combination of cycloheximide (CHX), dimethyl amino purine (DMAP), and anisomycin (ANY) on the activation of bovine oocytes, particularly on dynamics of MPF and MAPKs, embryonic developmental potential, and quality. The results showed that the cleavage and blastocyst rates, as well as levels of CCNB1, CDK1, p-CDK1Thr161, and p-CDK1Thr14-Tyr15, were similar among groups; ANY and ANY + CHX reduced the expression of ERK1/2 compared to DMAP-combinations (p < 0.05), whereas ANY + DMAP, CHX + DMAP, and ANY + CHX + DMAP reduced p-ERK1/2 compared to ANY and ANY + CHX treatments (p < 0.05). The quality of blastocysts in terms of cell counts, their allocation, and the numbers of TUNEL-positive cells did not differ among groups. However, transcript levels of POU5F1 were higher in embryos derived from ANY + CHX + DMAP treatment compared to other groups, while expression levels of CDX2 did not show differences. In addition, the BCL2A1/BAX ratio of the ANY + CHX + DMAP treatment was significantly low compared to the ANY treatment (p < 0.05) and did not differ significantly from the other treatments. In conclusion, oocyte activation by dual inhibition of protein synthesis and phosphorylation induces MPF inactivation without degradation of CCNB1, while MAPK inactivation occurs differentially between these inhibitors. Thus, although the combined use of these inhibitors does not affect early developmental competence in vitro, it positively impacts the expression of transcripts associated with embryonic quality.

Kinesin family member 11 promotes progression of hepatocellular carcinoma via the OCT4 pathway

Hepatocellular carcinoma (HCC) is the tumor with the second highest mortality rate worldwide. Recent research data show that KIF11, a member of the kinesin family (KIF), plays an important role in the progression of various tumors. However, its expression and molecular mechanism in HCC remain elusive. Here, we evaluated the potential role of KIF11 in HCC. The effect of KIF11 was evaluated using the hepatocellular carcinoma cell lines, LM3 and Huh7, after genetic or pharmacological treatment. Evaluating the role of KIF11 in the xenograft animal models using its specific inhibitor. The role of KIF11 was systematically evaluated using specimens obtained from the aforementioned animal and cell models after various in vivo and in vitro experiments. The clinicopathological analysis showed that KIF11 was expressed at high levels in patients with hepatocellular carcinoma. Cell experiments in vitro showed that KIF11 deficiency significantly slowed the proliferation of liver tumor cells. And in the experiment using liver cancer cells overexpressing OCT4, overexpression of OCT4 substantially increased the proliferation of tumor cells compared with tumor cells with KIF11 knockdown alone. Both in vitro cell experiment and in vivo xenotransplantation tumor experiment showed that monastrol, an inhibitor of KIF11, could effectively delay the proliferation and migration of tumor cells. Based on these results, KIF11 is expressed at high levels in hepatocellular carcinoma and promotes tumor proliferation in an OCT4-dependent manner. KIF11 may become a therapeutic target for hepatocellular carcinoma, and its inhibitor monastrol may become a clinical antitumor drug.

Leveraging a disulfidptosis-based signature to improve the survival and drug sensitivity of bladder cancer patients

Background

Disulfidptosis is a recently discovered form of cell death. However, its biological mechanisms in bladder cancer (BCa) are yet to be understood.

Methods

Disulfidptosis-related clusters were identified by consensus clustering. A disulfidptosis-related gene (DRG) prognostic model was established and verified in various datasets. A series of experiments including qRT-PCR, immunoblotting, IHC, CCK-8, EdU, wound-healing, transwell, dual-luciferase reporter, and ChIP assays were used to study the biological functions.

Results

We identified two DRG clusters, which exhibited distinct clinicopathological features, prognosis, and tumor immune microenvironment (TIME) landscapes. A DRG prognostic model with ten features (DCBLD2, JAM3, CSPG4, SCEL, GOLGA8A, CNTN1, APLP1, PTPRR, POU5F1, CTSE) was established and verified in several external datasets in terms of prognosis and immunotherapy response prediction. BCa patients with high DRG scores may be characterized by declined survival, inflamed TIME, and elevated tumor mutation burden. Besides, the correlation between DRG score and immune checkpoint genes and chemoradiotherapy-related genes indicated the implication of the model in personalized therapy. Furthermore, random survival forest analysis was performed to select the top important features within the model: POU5F1 and CTSE. qRT-PCR, immunoblotting, and immunohistochemistry assays showed the enhanced expression of CTSE in BCa tumor tissues. A series of phenotypic assays revealed the oncogenetic roles of CTSE in BCa cells. Mechanically, POU5F1 can transactivate CTSE, promoting BCa cell proliferation and metastasis.

Conclusions

Our study highlighted the disulfidptosis in the regulation of tumor progression, sensitivity to therapy, and survival of BCa patients. POU5F1 and CTSE may be potential therapeutic targets for the clinical treatment of BCa.

Comparison of SOX2 and POU5F1 Gene Expression in Leukapheresis-Derived CD34+ Cells before and during Cell Culture

Bone marrow is an abundant source of both hematopoietic as well as non-hematopoietic stem cells. Embryonic, fetal and stem cells located in tissues (adipose tissue, skin, myocardium and dental pulp) express core transcription factors, including the SOX2, POU5F1 and NANOG gene responsible for regeneration, proliferation and differentiation into daughter cells. The aim of the study was to examine the expression of SOX2 and POU5F1 genes in CD34-positive peripheral blood stem cells (CD34+ PBSCs) and to analyze the influence of cell culture on the expression of SOX2 and POU5F1 genes. The study material consisted of bone marrow-derived stem cells isolated by using leukapheresis from 40 hematooncology patients. Cells obtained in this process were subject to cytometric analysis to determine the content of CD34+ cells. CD34-positive cell separation was conducted using MACS separation. Cell cultures were set, and RNA was isolated. Real-time PCR was conducted in order to evaluate the expression of SOX2 and POU5F1 genes and the obtained data were subject to statistical analysis. We identified the expression of SOX2 and POU5F1 genes in the examined cells and demonstrated a statistically significant (p < 0.05) change in their expression in cell cultures. Short-term cell cultures (<6 days) were associated with an increase in the expression of SOX2 and POU5F1 genes. Thus, short-term cultivation of transplanted stem cells could be used to induce pluripotency, leading to better therapeutic effects.

Epigenetic Regulation of Driver Genes in Testicular Tumorigenesis

In testicular germ cell tumor type II (TGCT), a seminoma subtype expresses an induced pluripotent stem cell (iPSC) panel with four upregulated genes, OCT4/POU5F1, SOX17, KLF4, and MYC, and embryonal carcinoma (EC) has four upregulated genes, OCT4/POU5F1, SOX2, LIN28, and NANOG. The EC panel can reprogram cells into iPSC, and both iPSC and EC can differentiate into teratoma. This review summarizes the literature on epigenetic regulation of the genes. Epigenetic mechanisms, such as methylations of cytosines on the DNA string and methylations and acetylations of histone 3 lysines, regulate expression of these driver genes between the TGCT subtypes. In TGCT, the driver genes contribute to well-known clinical characteristics and the driver genes are also important for aggressive subtypes of many other malignancies. In conclusion, epigenetic regulation of the driver genes are important for TGCT and for oncology in general.

DNA barcoding and gene expression recording reveal the presence of cancer cells with unique properties during tumor progression

Tumors comprise diverse cancer cell populations with specific capabilities for adaptation to the tumor microenvironment, resistance to anticancer treatments, and metastatic dissemination. However, whether these populations are pre-existing in cancer cells or stochastically appear during tumor growth remains unclear. Here, we show the heterogeneous behaviors of cancer cells regarding response to anticancer drug treatments, formation of lung metastases, and expression of transcription factors related to cancer stem-like cells using a DNA barcoding and gene expression recording system. B16F10 cells maintained clonal diversity after treatment with HVJ-E, a UV-irradiated Sendai virus, and the anticancer drug dacarbazine. PBS treatment of the primary tumor and intravenous injection of B16F10 cells resulted in metastases formed from clones of multiple cell lineages. Conversely, BL6 and 4T1 cells developed spontaneous lung metastases by a small number of clones. Notably, an identical clone of 4T1 cells developed lung metastases in different mice, suggesting the existence of cells with high metastatic potential. Cas9-based transcription recording analysis in a human prostate cancer cell line revealed that specific cells express POU5F1 in response to an anticancer drug and sphere formation. Our findings provide insights into the diversity of cancer cells during tumor progression.

Linc-ROR Regulates POU5F1 and SOX2 by Competitively Binding miR-145-5p to Affect the Proliferation and Migration of Gastric Cancer Cells

Gastric cancer is the third leading cause of cancer-related deaths worldwide, and research on gastric cancer pathogenesis is fundamental. Long intergenic non-coding RNAs (lincRNAs) control cancer initiation and progression through several mechanisms, with the competitive endogenous RNA (ceRNA) regulatory network being the most common. In this study, in situ hybridization revealed that long intergenic non-protein coding RNA-regulator of reprogramming (linc-ROR) was highly expressed in gastric cancer cells and was mainly cytoplasmic-positive. Cell counting kit-8 (CCK-8), plate colony formation, wound healing, and Transwell assay revealed that linc-ROR knockdown impedes the growth, proliferation, and migration of gastric cancer cells, while linc-ROR overexpression promoted gastric cancer cell growth, migration, and colony formation ability. Combined with previous studies, the molecular mechanism axis of linc-ROR/miR-145-5-5p/POU5F1/SOX2 was verified. The expression of linc-ROR knockdown significantly suppressed the protein expression of POU5F1 and SOX2. Co-transfection with linc-ROR siRNA reverses the carcinogenic effect of the miR-145-5p inhibitor on gastric cancer cell proliferation, cloning, and migration. These findings lay a foundation for developing novel targets for gastric cancer treatment.

Comparison of POU5F1 gene expression and protein localization in two differentiated and undifferentiated spermatogonial stem cells

The POU domain, class 5, transcription factor 1 (POU5F1), plays a vital role in creating pluripotency and maintaining self-renewal of the spermatogonial stem cells (SSCs). In this experimental research, the gene and protein expression of POU5F1 in two populations of differentiated and undifferentiated spermatogonia were examined, by immunohistochemistry (IMH), immunocytochemistry (ICC) and Fluidigm real-time RT-PCR. Our study was extended with online databases and the creation of PPI networks. The results indicated that the POU5F1 protein was localized in the basal compartment of seminiferous tubules. Under in vitro conditions, isolated SSC colonies were ICC-positive for the POU5F1, but the protein expression level of POU5F1 in the undifferentiated populations was higher than that in differentiated. A significant POU5F1 mRNA expression was seen in passage 4 compared to passage 0 for both populations. POU5F1 has a significantly higher mRNA expression in undifferentiated SSCs than that in differentiated SSCs, also in mESCs than in SSC-like cells. Bioinformatic analysis on POU5F1 shows its impressive connection with other genes involved in spermatogonia differentiation. These results support the advanced investigations of spermatogonia differentiation, both in vitro and in vivo. A better understanding of the POU5F1 gene and its function during differentiation will give the scientific community an open perspective for the development of direct differentiation of SSC to other male germline cells which is very important in infertility treatment.

Advantage of clinical colchicine concentration to promote sorafenib or regorafenib anti-cancer effects on hepatocellular carcinoma

The advantage of colchicine to promote sorafenib or regorafenib anti-cancer effects on hepatocellular carcinoma (HCC) was investigated. Four primary cultured HCC cell lines (S103, S143, S160, S176) were studied by clinically achievable plasma sorafenib (5, 10 μg/mL), regorafenib (2, 4 μg/mL) and colchicine (4 ng/mL) concentrations. Sorafenib and regorafenib target genes and cancer stem cell markers (NANOG, POU5F1) were selected for experiments. Colchicine inhibited proliferation in all cell lines. Sorafenib inhibited proliferation only in S143 (5 μg/mL). Combined colchicine with sorafenib reversed the sorafenib effect on cellular proliferation from promotive to inhibitory in S103, and demonstrated anti-proliferative effects on other cell lines. Regorafenib inhibited proliferation in S103 (2 μg/mL), S176 (2 μg/mL) and S160 (4 μg/mL). Combined colchicine with regorafenib demonstrated equal or stronger anti-proliferative effects than regorafenib alone in all cell lines except S160. Combined colchicine obliterated or reduced the number of up-regulated target genes induced by sorafenib, and demonstrated equal or increased number of down-regulated target genes as compared with regorafenib alone. However, combined colchicine with regorafenib increased one up-regulated target gene in three cell lines. Colchicine obliterated or decreased the magnitude of up-regulated NANOG induced by sorafenib (S103, S143, S176) or regorafenib (S143), and combined with regorafenib could down-regulate NANOG (S160, S176). Adding colchicine to sorafenib or regorafenib showed inconsistent influence on POU5F1 expression as compared with sorafenib or regorafenib alone. The above results suggest that the anti-cancer effects of combined sorafenib with colchicine may be better than sorafenib alone. Colchicine may be added to regorafenib non-responders.

Pediatric Astrocytomas and Their Association With Polymorphisms in Embryonic Stem Cell Marker Genes

BACKGROUND

Embryonic stem cell markers, such as SOX2, NANOG, and OCT4, are transcription factors expressed in pluripotent stem cells, involved in the mediation of pluripotency and self-renewal. Especially after the discovery of cancer stem cells, these proteins have been associated with several types of neoplasia, including astrocytomas. In the pediatric population, astrocytomas are the most common solid neoplasia and present the highest mortality rates.

METHODS

Our study evaluated 5 polymorphisms in SOX2, NANOG, and POU5F1 genes in 101 pediatric astrocytoma samples.

RESULTS

We describe the associations between wild and polymorphic alleles in astrocytomas.

CONCLUSIONS

In our results, the intronic polymorphic G allele in SOX2 rs77677339 [G/A] had a borderline association with low-grade astrocytomas, and the intronic polymorphic T allele in NANOG rs10845877 [C/T] showed a higher frequency in grade 2, compared to grade 1 astrocytomas, thus showing promising results.

IMPACT

Our study is relevant because it shows a potential correlation between polymorphic embryonic stem cell marker genes and pediatric astrocytomas.

Kawasaki disease: lncRNA Slco4a1 regulates the progression of human umbilical vein endothelial cells by targeting the miR-335-5p/POU5F1 axis

BACKGROUND

Kawasaki disease (KD) is an autoimmune disease with systemic vasculitis as the main pathological change, and is most common in children under 5. The role of long non-coding RNAs (lncRNAs) in human diseases has been highlighted. LncRNA Slco4a1 was reported to promote cell growth and act as an oncogenic regulator in cancer. However, the role of lncRNA Slco4a1 in KD remains unclear. This study aimed to investigate the role and mechanism of lncRNA Slco4a1 in KD.

METHODS

Enzyme linked immunosorbent assay (ELISA), qRT-PCR, Western blot, and terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) staining were conducted to explore the function of lncRNA Slco4a1. The interaction between POU5F1 and miR-335-5p was analyzed by the RIP assay and dual luciferase assay.

RESULTS

LncRNA Slco4a1 was significantly upregulated in the serum of KD patients compared with healthy controls. LncRNA Slco4a1 was upregulated in human umbilical vein endothelial cells (HUVECs) stimulated with KD serum. LncRNA Slco4a1 overexpression could promote the expression of inflammatory factors and apoptosis in HUVECs. The number of inflammatory cells and the infiltration area of the coronary artery in KD rats were decreased after lncRNA Slco4a1 silencing. Furthermore, lncRNA Slco4a1 is a sponge of miR-335-5p and negatively regulated the expression of miR-335-5p. POU5F1 was the downstream target of miR-335-5p, and miR-335-5p overexpression could upregulate the expression of POU5F1. Additionally, miR-335-5p overexpression could inhibit the expression of inflammatory factors and apoptosis in HUVECs. We further investigated the effect of lncRNA Slco4a1 on the mitogen-activated protein kinase (MAPK) signaling pathway, and the results showed that lncRNA Slco4a1 could promote the activation of the MAPK signaling pathway.

CONCLUSIONS

Together, these results indicated that lncRNA Slco4a1 could regulate the progression of HUVECs in KD by targeting the miR-335-5p/POU5F1 axis, providing new insights for KD treatment.

Therapeutic Response of Soft Tissue Sarcoma With Novel SS18-POU5F1 Fusion: A Case Report

A novel SS18-POU5F1 fusion gene was recently reported in soft tissue sarcoma occurring in three adolescent and young adult patients. Herein, we firstly reported the treatment response of SS18-POU5F1 sarcoma to immune checkpoint inhibitor, angiogenesis inhibitor, chemotherapy and radiotherapy. Our patient demonstrated no response to various systemic therapies including immune checkpoint inhibitor, angiogenesis inhibitor and chemotherapy. However, we noted that the SS18-POU5F1 sarcoma had a quick, robust but transient clinical response to radiotherapy. Further studies are needed to elucidate the mechanism underlying the different tumor response to radiotherapy and systemic therapy in this kind of tumor.

A Review of OCT4 Functions and Applications to Equine Embryos

OCT4 is a core transcription factor involved in pluripotency maintenance in the early mammalian embryo. The POU5F1 gene that encodes the OCT4 protein is highly conserved across species, suggesting conserved function. However, studies in several species including mice, cattle, and pigs, suggest that there are differences in where and when OCT4 is expressed. Specifically, in the horse, several studies have shown that exposure to the uterine environment may be necessary to induce OCT4 expression restriction to the inner cell mass (ICM) of the developing embryo, suggesting that there may be equine-specific extrinsic regulators of OCT4 expression that have not yet been investigated. However, an alternative hypothesis is that this restriction may not be evident in equine embryos because of our inability to culture them to the epiblast stage, preventing the observation of this restriction. In vitro studies have identified that OCT4 is expressed in the immature equine oocyte and in the early equine embryo, but OCT4 expression has not been studied after the formation of the ICM in the equine embryo. Despite the gaps in knowledge about equine-specific functions of OCT4, this factor has been used in studies assessing equine embryonic stem cells and to induce pluripotency in equine somatic cells. This review describes the role of OCT4 in the equine embryo and its applications in equine stem cell research.

Long intergenic non-coding RNA, regulator of reprogramming (LINC-ROR) over-expression predicts poor prognosis in renal cell carcinoma

INTRODUCTION

Long intergenic non-coding RNA, regulator of reprogramming (LINC-ROR) is a newly identified cytoplasmic long non-coding RNA (lncRNA) implicated in cell longevity and apoptosis. We aimed in the current work for the first time to investigate the association of the expression profiles of LINC-ROR and three stem-related transcriptional factors with clinicopathological data and their impact on renal cell carcinoma (RCC) progression in a sample of RCC patients.

MATERIAL AND METHODS

Expression levels of LINC-ROR and stemness-related factors: SOX2, NANOG, and POU5F1 were detected in 60 formalin-fixed, paraffin-embedded tissues, and their paired adjacent non-cancer tissues (n = 60) by using real-time qRT-PCR analysis. Additionally, the expression profiles were compared with the available clinicopathological features.

RESULTS

The genes studied were markedly up-regulated in RCC (medians and interquartile ranges were 30.3 (1.84-235.5), 10.2 (1.84-53.9), 5.39 (0.94-23.5), and 12.5 (1.61-43.2) for LINC-ROR, SOX2, NANOG, and POU5F1, respectively) relative to paired non-cancer tissue. High expression levels were associated with poor prognosis in terms of tumour undifferentiation (for LINC-ROR, SOX2, and NANOG), lymph node infiltration (for SOX2), postoperative recurrence (for LINC-ROR and SOX2), and shorter overall survival (OS) and progression-free survival (for all genes studied). The best curve for OS prediction was constructed with LINC-ROR data (area under the receiver operating characteristic curve (AUC) = 0.804 at a cut-off value of 72.7, sensitivity 78.9%, and specificity 80.5%).

CONCLUSIONS

Collectively, aberrant LINC-ROR and pluripotent gene expression may be recognised as prognostic markers for RCC. Future functional studies are highly recommended to validate the study findings.

Diagnostic significance and carcinogenic mechanism of pan-cancer gene POU5F1 in liver hepatocellular carcinoma

BACKGROUND

The prognostic and clinicopathological significance of POU Class 5 Homeobox 1 (POU5F1) among various cancers are disputable heretofore. The diagnostic value and functional mechanism of POU5F1 in liver hepatocellular carcinoma (LIHC) have not been studied thoroughly.

METHODS

An integrative strategy of meta-analysis, bioinformatics, and wet-lab approach was used to explore the diagnostic and prognostic significance of POU5F1 in various types of tumors, especially in LIHC. Meta-analysis was utilized to investigate the impact of POU5F1 on prognosis and clinicopathological parameters in various cancers. The expression level and diagnostic value of POU5F1 were assessed by qPCR in plasma collected from LIHC patients and controls. The correlation between POU5F1 and tumor infiltrating immune cells (TIICs) in LIHC was evaluated by CIBERSORT. Gene set enrichment analysis (GSEA) was performed based on TCGA. Hub genes and related pathways were identified on the basis of co-expression genes of POU5F1.

RESULTS

Elevated POU5F1 was associated with poor OS, DFS, RFS, and DSS in various cancers. POU5F1 was confirmed as an independent risk factor for LIHC and correlated with tumor occurrence, stage, and invasion depth. The combination of POU5F1 and AFP in plasma was with high diagnostic validity (AUC = 0.902, p < .001). Specifically, the level of POU5F1 was correlated with infiltrating levels of B cells, T cells, dendritic cells, and monocytes in LIHC. GSEA indicated that POU5F1 participated in multiple cancer-related pathways and cell proliferation pathways. Moreover, CBX3, CCHCR1, and NFYC were filtered as the central hub genes of POU5F1.

CONCLUSION

Our study identified POU5F1 as a pan-cancer gene that could not only be a prognostic and diagnostic biomarker in various cancers, especially in LIHC, but functionally carcinogenic in LIHC.

Undifferentiated round cell sarcomas with novel SS18-POU5F1 fusions

Despite significant recent advances in characterizing the molecular pathogenesis of undifferentiated round cell neoplasms, rare cases remain unclassified. Here, we report two distinctive undifferentiated round cell tumors occurring in young adults. One tumor presented intrabdominally and the other arose within the abdominal wall. One patient died of disease following local and distance recurrence, despite aggressive chemotherapy and radiotherapy. Morphologically, both tumors were similarly composed of primitive round to epithelioid cells arranged in nests, sheets, and trabecular patterns. The cytoplasm was scant and amphophilic, while the nuclei were round and uniform with brisk mitotic activity. Focal necrosis was present. Immunohistochemically, both tumors were variably positive for S100 and EMA, and one case focally expressed cytokeratin and TLE1. Targeted RNA sequencing revealed in both an identical SS18-POU5F1 fusion gene. Fluorescence in situ hybridization was performed which confirmed SS18 and POU5F1 gene rearrangements. Expression data, relative to over 200 other mesenchymal neoplasms that had undergone targeted RNA sequencing on the same platform, suggested the SS18-POU5F1 tumors cluster with EWSR1/FUS-POU5F1-positive myoepithelial tumors. In view of our limited sample size, additional studies are needed to characterize the breadth of clinical and pathologic findings in these neoplasms. In addition, further investigation is necessary to determine whether this entity represents a clinically aggressive and phenotypically undifferentiated variant of myoepithelial tumors, or perhaps an altogether novel category of undifferentiated round cell sarcoma.

A morphologic and molecular reappraisal of myoepithelial tumors of soft tissue, bone, and viscera with EWSR1 and FUS gene rearrangements

Myoepithelial tumors (MET) represent a clinicopathologically heterogeneous group of tumors, ranging from benign to highly aggressive lesions. Although MET arising in soft tissue, bone, or viscera share morphologic and immunophenotypic overlap with their salivary gland and cutaneous counterparts, there is still controversy regarding their genetic relationship. Half of MET of soft tissue and bone harbor EWSR1 or FUS related fusions, while MET arising in the salivary gland and skin often show PLAG1 and HMGA2 gene rearrangements. Regardless of the site of origin, the gold standard in diagnosing a MET relies on demonstrating its "myoepithelial immunophenotype" of positivity for EMA/CK and S100 protein or GFAP. However, the morphologic spectrum of MET in soft tissue and bone is quite broad and the above immunoprofile is nonspecific, being shared by other pathogenetically unrelated neoplasms. Moreover, rare MET lack a diagnostic immunoprofile but shows instead the characteristic gene fusions. In this study, we analyzed a large cohort of 66 MET with EWSR1 and FUS gene rearrangements spanning various clinical presentations, to better define their morphologic spectrum and establish relevant pathologic-molecular correlations. Genetic analysis was carried out by FISH for EWSR1/FUS rearrangements and potential partners, and/or by targeted RNA sequencing. Then, 82% showed EWSR1 rearrangement, while 18% had FUS abnormalities. EWSR1-POU5F1 occurred with predilection in malignant MET in children and young adults and these tumors had nested epithelioid morphology and clear cytoplasm. In contrast, EWSR1/FUS-PBX1/3 fusions were associated with benign and sclerotic spindle cell morphology. Tumors with EWSR1-KLF17 showed chordoma-like morphology. Our results demonstrate striking morphologic-molecular correlations in MET of bone, soft tissue and viscera, which might have implications in their clinical behavior.

Humanized Stem Cell Models of Pediatric Medulloblastoma Reveal an Oct4/mTOR Axis that Promotes Malignancy

Medulloblastoma (MB), the most frequent malignant childhood brain tumor, can arise from cellular malfunctions during hindbrain development. Here we generate humanized models for Sonic Hedgehog (SHH)-subgroup MB via MYCN overexpression in primary human hindbrain-derived neuroepithelial stem (hbNES) cells or iPSC-derived NES cells, which display a range of aggressive phenotypes upon xenografting. iPSC-derived NES tumors develop quickly with leptomeningeal dissemination, whereas hbNES-derived cells exhibit delayed tumor formation with less dissemination. Methylation and expression profiling show that tumors from both origins recapitulate hallmarks of infant SHH MB and reveal that mTOR activation, as a result of increased Oct4, promotes aggressiveness of human SHH tumors. Targeting mTOR decreases cell viability and prolongs survival, showing the utility of these varied models for dissecting mechanisms mediating tumor aggression and demonstrating the value of humanized models for a better understanding of pediatric cancers.

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Human iPSC-derived or primary neuroepithelial stem cells can be transformed by MYCN

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MYCN drives infant SHH medulloblastoma with clinically relevant features

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Epigenetically regulated Oct4 promotes mTOR hyperactivation in infant SHH tumors

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mTOR inhibition efficiently targets metastatic SHH medulloblastoma models and PDXs

Comparison of Epigenetic Modifier Genes in Bovine Adipose Tissue-Derived Stem Cell Based Embryos, as Donors, with In Vitro and Parthenogenesis Embryos

Objective

Regarding that undifferentiated mesenchymal stem cells, as donor cells, require less epigenetic reprogramming, possibility of using bovine adipose tissue-derived stem cells (BASCs) with low level of DNMTs and HDACs expression was evaluated.

Materials and Methods

In this experimental study, we examined gene expression of epigenetic modifiers including DNA methyltransferases (DNMT1, DNMT3A and DNMT3B) and histone deacetylases (HDAC1-3), as well as protein levels of histone H3 acetylation at lysine 9 (H3K9ac) and POU5F1 (also known as OCT4) at two stages of preimplantation development among in vitro fertilization (IVF), parthenogenetic activation (PA) and somatic cell nuclear transfer (SCNT) groups.

Results

The results revealed that developmental competence of IVF embryos was higher than SCNT embryos (P<0.05). In the PA and SCNT groups, DNMT1, HDAC2 and HDAC3 mRNA were overexpressed (P<0.05), and proteins levels of H3K9ac and POU5F1 were reduced at 6-8 cells and blastocyst stages compared to IVF (P<0.05). The mRNA expression of DNMT1 an<0.05) in both developmental stages (except HDAC1 in blastocyst stage).

Conclusion

The SCNT embryos derived from BASCs have endured considerable nuclear reprogramming during early embryo development. Comparison of PA and SCNT blastocysts demonstrated that HDAC1 and DNMT1 may attribute to developmental competence variability of bovine embryos.

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.

HNF1A is a novel oncogene that regulates human pancreatic cancer stem cell properties

The biological properties of pancreatic cancer stem cells (PCSCs) remain incompletely defined and the central regulators are unknown. By bioinformatic analysis of a human PCSC-enriched gene signature, we identified the transcription factor HNF1A as a putative central regulator of PCSC function. Levels of HNF1A and its target genes were found to be elevated in PCSCs and tumorspheres, and depletion of HNF1A resulted in growth inhibition, apoptosis, impaired tumorsphere formation, decreased PCSC marker expression, and downregulation of POU5F1/OCT4 expression. Conversely, HNF1A overexpression increased PCSC marker expression and tumorsphere formation in pancreatic cancer cells and drove pancreatic ductal adenocarcinoma (PDA) cell growth. Importantly, depletion of HNF1A in xenografts impaired tumor growth and depleted PCSC marker-positive cells in vivo. Finally, we established an HNF1A-dependent gene signature in PDA cells that significantly correlated with reduced survivability in patients. These findings identify HNF1A as a central transcriptional regulator of PCSC properties and novel oncogene in PDA.

Radiation resistance of the lung adenocarcinoma is related to the AKT-Onzin-POU5F1 axis

Non-small cell lung carcinoma is the predominant type of lung cancer, and shows an easily developable tolerance to radiotherapy. Cancer stem cells are suggested to be involved in the resistance against therapies. Onzin might be accumulated during the process tumor overcoming the radiation stress. To address the relationship between Onzin, stemness and radiation resistance, we treated the lung cancer tumor bearing mice with radiaotherapy and observed the differences between radiation sensitive (RS) and resistant (RR) tumors. Immunohistochemistry and HE staining were used to observe Onzin and POU5F1 expression in tumor tissues. Quantitative realtime-PCR and Western blot were applied for Onzin and POU5F1 in tumors and cells. In-vitro cellular viability was assessed by CCK8 methods for tumor derived cells. The stably transfected A549 cell lines overexpressing Onzin were generated through lentivirus transfection. After radiotherapy, those RR adenocarcinoma tumors and cells derived from them showed an increased Onzin expression. Further, RR cells were found upregulated stemness, indicated by increased sphericity and proliferation, as well as POU5F1 expression. Next, we overexpressed Onzin in the A549 cells and found an elevated POU5F1 expression, increased proliferation, and enhanced sphericity. Moreover, this could be suppressed by the AKT inhibitor MK-2260. In vivo, the A549 cells overexpressing Onzin showed not only higher tumor formation capability and growth, but also a significant resistance to radiation. Taken together, RR tumors have upregulated Onzin and POU5F1 expression. Ectopic expression of Onzin promotes the POU5F1 expression as well as stemness functions, and confers adenocarcinomas the resistance to radiotherapy.

High OCT4A levels drive tumorigenicity and metastatic potential of medulloblastoma cells

Medulloblastoma is a highly aggressive pediatric brain tumor, in which sporadic expression of the pluripotency factor OCT4 has been recently correlated with poor patient survival. However the contribution of specific OCT4 isoforms to tumor aggressiveness is still poorly understood. Here, we report that medulloblastoma cells stably overexpressing the OCT4A isoform displayed enhanced clonogenic, tumorsphere generation, and invasion capabilities. Moreover, in an orthotopic metastatic model of medulloblastoma, OCT4A overexpressing cells generated more developed, aggressive and infiltrative tumors, with tumor-bearing mice attaining advanced metastatic disease and shorter survival rates. Pro-oncogenic OCT4A effects were expression-level dependent and accompanied by distinct chromosomal aberrations. OCT4A overexpression in medulloblastoma cells also induced a marked differential expression of non-coding RNAs, including poorly characterized long non-coding RNAs and small nucleolar RNAs. Altogether, our findings support the relevance of pluripotency-related factors in the aggravation of medulloblastoma traits classically associated with poor clinical outcome, and underscore the prognostic and therapeutic value of OCT4A in this challenging type of pediatric brain cancer.

Tissue organization alters gene expression in equine induced trophectoderm cells

Rapid morphological and gene expression changes occur during the early formation of a mammalian blastocyst. Critical to successful retention of the blastocyst and pregnancy is a functional trophectoderm (TE) that supplies the developing embryo with paracrine factors and hormones. The contribution of TE conformational changes to gene expression was examined in equine induced trophoblast (iTr) cells. Equine iTr cells were cultured as monolayers or in suspension to form spheres. The spheres are hollow and structurally reminiscent of native equine blastocysts. Total RNA was isolated from iTr monolayers and spheres and analyzed by RNA sequencing. An average of 32.2 and 31million aligned reads were analyzed for the spheres and monolayers, respectively. Forty-four genes were unique to monolayers and 45 genes were expressed only in spheres. Conformation did not affect expression of CDX2, POU5F1, TEAD4, ETS2, ELF3, GATA2 or TFAP2A, the core gene network of native TE. Bioinformatic analysis was used to identify classes of genes differentially expressed in response to changes in tissue shape. In both iTr spheres and monolayers, the majority of the differentially expressed genes were associated with binding activity in cellular, developmental and metabolic processes. Inherent to protein:protein interactions, several receptor-ligand families were identified in iTr cells with enrichment of genes coding for PI3-kinase and MAPK signaling intermediates. Our results provide evidence for ligand initiated kinase signaling pathways that underlie early trophectoderm structural changes.

miR-335 negatively regulates osteosarcoma stem cell-like properties by targeting POU5F1

Background

Evidence is accumulating to link cancer stem cells to the pathogenesis and progression of osteosarcoma. The aim of this study is to investigate the role of miR-335 in osteosarcoma stem cells.

Methods

Tumor spheroid culture and flow cytometry were applied to screen out osteosarcoma stem cells. Real-time quantitative PCR was used to detect the expression level of miR-335 in MG63, U2OS and 143B osteosarcoma stem cells. The relationship of miR-335 expression with osteosarcoma stem cells was then analyzed. Transwell assay and transplantation assay were performed to elucidate biological effects of miR-335 on cell invasion and vivo tumor formation. Western Blot and luciferase assays were executed to investigate the regulation of POU5F1 by miR-335.

Results

The expression of miR-335 in osteosarcoma stem cells was lower than their differentiated counterparts. Cells expressing miR-335 possessed decreased stem cell-like properties. Gain or loss of function assays were applied to find that miR-335 antagonist promoted stem cell-like properties as well as invasion. Luciferase report and transfection assay showed that POU5F1 was downregulated by miR-335. Pre-miR-335 resulted in tumor enhanced sensitivity to traditional chemotherapy, whereas anti-miR-335 promoted chemoresistance. Finally, the inhibitory effect of miR-335 on in vivo tumor formation showed that combination of pre-miR-335 with cisplatin further reduced the tumor size, and miR-335 brought down the sphere formation capacity induced by cisplatin.

Conclusions

The current study demonstrates that miR-335 negatively regulates osteosarcoma stem cell-like properties by targeting POU5F1, and miR-335 could target CSCs to synergize with traditional chemotherapeutic agents to overcome osteosarcoma.

Cancer Stem Cell Gene Variants Predict Disease Recurrence in Patients Treated with Radical Prostatectomy for Prostate Cancer

Background: Cancer stem cells (CSCs) are involved in tumor progression and drug resistance. We hypothesized that variants in CSC marker genes influence treatment outcomes in prostate cancer. Methods: Ten potentially functional single nucleotide polymorphisms (SNPs) in seven prostate CSC marker genes, TACSTD2, PROM1, ITGA2, POU5F1, EZH2, PSCA, and CD44, were selected for analysis of their association with disease recurrence by Kaplan-Meier analysis and Cox regression in a cohort of 320 patients with localized prostate cancer receiving radical prostatectomy. Results: We identified one independent SNP, rs2394882, in POU5F1 that was associated with prostate cancer recurrence (hazard ratio 0.32, 95% confidence interval 0.14-0.71, P = 0.005) after adjustment for known clinical predictors. Further in silico functional analyses revealed that rs2394882 affects POU5F1 expression, which in turn is significantly correlated with prostate cancer aggressiveness and patient prognosis. Conclusion: Our results suggest that rs2394882 is prognostically relevant in prostate cancer, possibly by modulating the expression of the CSC gene POU5F1.

Optimized inducible shRNA and CRISPR/Cas9 platforms for in vitro studies of human development using hPSCs

Inducible loss of gene function experiments are necessary to uncover mechanisms underlying development, physiology and disease. However, current methods are complex, lack robustness and do not work in multiple cell types. Here we address these limitations by developing single-step optimized inducible gene knockdown or knockout (sOPTiKD or sOPTiKO) platforms. These are based on genetic engineering of human genomic safe harbors combined with an improved tetracycline-inducible system and CRISPR/Cas9 technology. We exemplify the efficacy of these methods in human pluripotent stem cells (hPSCs), and show that generation of sOPTiKD/KO hPSCs is simple, rapid and allows tightly controlled individual or multiplexed gene knockdown or knockout in hPSCs and in a wide variety of differentiated cells. Finally, we illustrate the general applicability of this approach by investigating the function of transcription factors (OCT4 and T), cell cycle regulators (cyclin D family members) and epigenetic modifiers (DPY30). Overall, sOPTiKD and sOPTiKO provide a unique opportunity for functional analyses in multiple cell types relevant for the study of human development.

Transcription factor Oct4 promotes osteosarcoma by regulating lncRNA AK055347

Osteosarcoma is the most common primary bone tumor in children and adolescents, typically presenting with a poor prognosis. Octamer-binding transcription factor 4 (Oct4) protein, encoded by the POU class 5 homeobox 1 gene, is important in maintaining self-renewal of pluripotent stem cells, and is closely associated with cancer. However, its role in osteosarcoma remains to be elucidated. The present study observed Oct4 was markedly increased in osteosarcoma cell lines and in human osteosarcoma tissue samples. Following Oct4 downregulation by small interfering RNA (siRNA) in osteosarcoma F5M2 cells, the cells exhibited significant decreases in proliferation and invasion ability, and an increase in cell apoptosis. Notably, downregulation of Oct4 decreased the expression of AK055347, a newly identified long noncoding RNA (lncRNA) in human tissues. The downregulation of AK055347 by siRNA resulted in a significant suppressive effect on proliferative and invasive ability, and promotion of cell apoptosis in osteosarcoma cells. Thus, the current study suggests Oct4 exerts a promoting effect in osteosarcoma, and identifies a novel lncRNA in osteosarcoma progression.

Hydroxyl-HIF2-alpha is potential therapeutic target for renal cell carcinomas

Dormant cancer cells are deprivation-resistant, and cause a number of problems for therapeutic approaches for cancers. Renal cell carcinomas (RCCs) include deprivation-resistant cells that are resistant to various treatments. In this study, the specific characteristics of deprivation-resistant cells were transcriptionally identified by next generation sequencing. The hypoxia-inducible factors (HIF) transcription factor network was significantly enhanced in deprivation-resistant RCCs compared to the sensitive RCCs. Deprivation-resistant RCCs, that had lost Von Hippel-Lindau tumor suppressor expression, expressed hydroxyl-HIF2-alpha in the nucleus, but not sensitive-RCCs. Hydroxyl-HIF-alpha was also expressed in nuclei of RCC tissue samples. Knockdown for HIF2-alpha, but not HIF1-alpha, induced cell death related to a reduction in HIF-related gene expression in deprivation-resistant RCC cells. Chetomin, a nuclear HIF-inhibitor, induced marked level of cytotoxicity in deprivation-resistant cells, similar to the knockdown of HIF2-alpha. Therefore, hydroxyl-HIF2-alpha might be a potential therapeutic target for RCCs.

Analysis of POU5F1, c-Kit, PLAP, AP2γ and SALL4 in gonocytes of patients with cryptorchidism

Cryptorchidism is a risk factor for the development of testicular germ cell tumors (TGCTs). The most common type of TGCT in cryptorchidism is seminoma. The intratubular germ cell neoplasia unclassified (ITGCNU) is a histological pattern preceding the development of seminomas and non-seminomas. It was suggested that in patients with cryptorchidism, the gonocytes remained undifferentiated with pluripotent abilities expressing proteins like POU domain class 5 transcription factor 1 (POU5F1), tyrosine kinase receptor c-Kit, placental-like alkaline phosphatase (PLAP), the transcription factor AP2γ and sal-like protein 4 (SALL4) that confer to the gonocytes this ability and therefore make them susceptible to develop ITGCNU. The aim of the present study was to determine if the gonocytes of patients with cryptorchidism express POU5F1, c-Kit, PLAP, AP2γ and SALL4 proteins after their differentiation period. Based on this, we evaluated samples of testicular tissue from newborns to 16-year old subjects with or without cryptorchidism in search of POU5F1, c-Kit, PLAP, AP2γ and SALL4 using immunocytochemical method, the results of which were validated by RT-PCR. The results showed that control subjects witnessed a down-regulation in the expression of these five proteins in the first year of life, which eventually disappeared. On the other hand, it was determined that 21.6% (8/37) of the patients with cryptorchidism continued to express, at least, one of the proteins analyzed in this study after the second year of life. And only 5.4% (2/37) of the patients were positive to the five markers. These data sustain the proposed hypothesis that in cryptorchid patients, ITGCNU arises from gonocytes that fail in their differentiation process to spermatogonia with conservation of the proteins (POU5F1, c-Kit, PLAP, AP2γ and SALL4) that maintain pluripotency and undifferentiated characteristics and which are responsible for making the gonocytes susceptible to malignancy. However, we cannot guarantee that these patients present neoplastic transformation.

Epigenetic regulation of human adipose-derived stem cells differentiation

Adult stem cells have more restricted differentiation potential than embryonic stem cells (ESCs), but upon appropriate stimulation can differentiate into cells of different germ layers. Epigenetic factors, including DNA modifications, take a significant part in regulation of pluripotency and differentiation of ESCs. Less is known about the epigenetic regulation of these processes in adult stem cells. Gene expression profile and location of DNA modifications in adipose-derived stem cells (ADSCs) and their osteogenically differentiated lineages were analyzed using Agilent microarrays. Methylation-specific PCR and restriction-based quantitative PCR were applied for 5-methylcytosine (5mC) and 5-hydroxymethylcytosine (5hmC) detection in selected loci. The level of DNA modifications in the POU5F1 locus was quantified with deep sequencing. Expression levels of selected genes were assayed by real-time PCR. ADSCs differentiation into osteogenic lineages involved marked changes in both 5mC and 5hmC profiles, but 5hmC changes were more abundant. 5mC losses and 5hmC gains were the main events observed during ADSCs differentiation, and were accompanied by increased expression of TET1 (P = 0.009). In ADSCs, POU5F1 was better expressed than NANOG or SOX2 (P ≤ 0.001). Both 5mC and 5hmC marks were present in the POU5F1 locus, but only hydroxymethylation of specific cytosine showed significant effect on the gene expression. In summary, the data of our study suggest significant involvement of changes in 5hmC profile during the differentiation of human adult stem cells.

High-resolution molecular validation of self-renewal and spontaneous differentiation in clinical-grade adipose-tissue derived human mesenchymal stem cells

Improving the effectiveness of adipose-tissue derived human mesenchymal stromal/stem cells (AMSCs) for skeletal therapies requires a detailed characterization of mechanisms supporting cell proliferation and multi-potency. We investigated the molecular phenotype of AMSCs that were either actively proliferating in platelet lysate or in a basal non-proliferative state. Flow cytometry combined with high-throughput RNA sequencing (RNASeq) and RT-qPCR analyses validate that AMSCs express classic mesenchymal cell surface markers (e.g., CD44, CD73/NT5E, CD90/THY1, and CD105/ENG). Expression of CD90 is selectively elevated at confluence. Self-renewing AMSCs express a standard cell cycle program that successively mediates DNA replication, chromatin packaging, cyto-architectural enlargement, and mitotic division. Confluent AMSCs preferentially express genes involved in extracellular matrix (ECM) formation and cellular communication. For example, cell cycle-related biomarkers (e.g., cyclins E2 and B2, transcription factor E2F1) and histone-related genes (e.g., H4, HINFP, NPAT) are elevated in proliferating AMSCs, while ECM genes are strongly upregulated (>10-fold) in quiescent AMSCs. AMSCs also express pluripotency genes (e.g., POU5F1, NANOG, KLF4) and early mesenchymal markers (e.g., NES, ACTA2) consistent with their multipotent phenotype. Strikingly, AMSCs modulate expression of WNT signaling components and switch production of WNT ligands (from WNT5A/WNT5B/WNT7B to WNT2/WNT2B), while upregulating WNT-related genes (WISP2, SFRP2, and SFRP4). Furthermore, post-proliferative AMSCs spontaneously express fibroblastic, osteogenic, chondrogenic, and adipogenic biomarkers when maintained in confluent cultures. Our findings validate the biological properties of self-renewing and multi-potent AMSCs by providing high-resolution quality control data that support their clinical versatility.

Effect of epigenetic modification with trichostatin A and S-adenosylhomocysteine on developmental competence and POU5F1-EGFP expression of interspecies cloned embryos in dog

Adult canine fibroblasts stably transfected with either cytomegalovirus (CMV) or POU5F1 promoter-driven enhanced green fluorescent protein (EGFP) were used to investigate if pre-treatment of these donor cells with two epigenetic drugs [trichostatin A (TSA), or S-adenosylhomocysteine (SAH)] can improve the efficiency of interspecies somatic cell nuclear transfer (iSCNT). Fluorescence-activated cell sorting (FACS), analyses revealed that TSA, but not SAH, treatment of both transgenic and non-transgenic fibroblasts significantly increased acetylation levels compared with untreated relatives. The expression levels of Bcl2 and P53 were significantly affected in TSA-treated cells compared with untreated cells, whereas SAH treatment had no significant effect on cell apoptosis. Irrespective of epigenetic modification, dog/bovine iSCNT embryos had overall similar rates of cleavage and development to 8-16-cell and morula stages in non-transgenic groups. For transgenic reconstructed embryos, however, TSA and SAH could significantly improve development to 8-16-cell and morula stages compared with control. Even though, irrespective of cell transgenesis and epigenetic modification, none of the iSCNT embryos developed to the blastocyst stage. The iSCNT embryos carrying CMV-EGFP expressed EGFP at all developmental stages (2-cell, 4-cell, 8-16-cell, and morula) without mosaicism, while no POU5F1-EGFP signal was observed in any stage of developing iSCNT embryos irrespective of TSA/SAH epigenetic modifications. These results indicated that bovine oocytes partially remodel canine fibroblasts and that TSA and SAH have marginal beneficial effects on this process.

A Role for OCT4 in Tumor Initiation of Drug-Resistant Prostate Cancer Cells

Drug resistance remains a clinical challenge in cancer treatment due to poor understanding of underlying mechanisms. We have established several drug-resistant prostate cancer cell lines by long-term culture in medium containing chemotherapeutic drugs. These resistant lines displayed a significant increase in side population cells due to overexpression of drug efflux pumps including ABCG2/BCRP and MDR1/Pgp. To uncover potential mechanisms underlying drug resistance, we performed microarray analysis to identify differentially expressed genes in 2 drug-resistant lines. We observed that POU5F1/OCT4, a transcription factor key to regulating pluripotency in embryonic stem cells, was upregulated in drug-resistant lines and accompanied by transcriptional activation of a set of its known target genes. Upregulation of OCT4 in drug-resistant cells was validated by RT-PCR and sequencing of PCR products as well as confirmation by Western blot and specific shRNA knockdown. Analysis of the regulatory region of POU5F1/OCT4 revealed a reduction of methylation in drug-resistant cell lines. Furthermore, these drug-resistant cells exhibited a significant increase in tumorigenicity in vivo. Subcutaneous inoculation of as few as 10 drug-resistant cells could initiate tumor formation in SCID mice, whereas no detectable tumors were observed from the parental line under similar conditions, suggesting that these drug-resistant cells may be enriched for tumor-initiating cells. Knocking down OCT4 expression by specific shRNAs attenuated growth of drug-resistant cells. Our data suggest that OCT4 re-expression in cancer cells may play an important role in carcinogenesis and provide one possible mechanism by which cancer cells acquire/maintain a drug-resistant phenotype.