Oct4 expression revisited: potential pitfalls for data misinterpretation in stem cell research

2008 ◽  
Vol 389 (7) ◽  
Author(s):  
Stefanie Liedtke ◽  
Milaid Stephan ◽  
Gesine Kögler
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Adult Stem Cells ◽  
Mononuclear Cells ◽  
Embryonic Stem ◽  
Human Tumor ◽  
Stem Cell Differentiation ◽  
Self Renewal ◽  
Oct4 Expression

Abstract The octamer-binding transcription factor 4 gene encodes a nuclear protein (Oct4, also known as Pou5F1 and Oct3/4) that belongs to a family of transcription factors containing the POU DNA-binding domain. Expression can be detected in embryonic stem cells as well as in adult stem cells, such as bone marrow-derived mesenchymal stem cells. Expression of Oct4 is downregulated coincident with stem cell differentiation and loss of expression leading to differentiation. A role for maintaining pluripotency and self-renewal of embryonic stem cells is ascribed to Oct4 as a pluripotency marker. Results describing Oct4 expression in differentiated cells, including peripheral blood mononuclear cells (PBMCs), neonatal and adult stem cells, as well as cancer cells, must be interpreted with caution. In several publications, Oct4 has been ascribed a function in maintaining self-renewal of adult stem cells. In contrast, other publications reported Oct4 expression in human tumor cells. Here, we summarize the recent findings on Oct4 expression and present possibilities and reasons why several false positive results on Oct4 expression still occur in the recent literature. Also, simple solutions are provided to avoid these positive signals.

Oct4 and Its Pseudogenes Confuse Stem Cell Research.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 3700-3700
Author(s):  
Stefanie Liedtke ◽  
Jürgen Enczmann ◽  
Simon Waclawczyk ◽  
Peter Wernet ◽  
Gesine Kögler
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Adult Stem Cells ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Pcr Analysis ◽  
Rt Pcr ◽  
Differentiated Cells ◽  
Alternatively Spliced

Abstract Octamer-binding transcription factor 4 (Oct4) encodes a nuclear protein that belongs to a family of transcription factors containing the POU DNA binding domain. It is specifically expressed in embryonic stem cells but can also be detected in adult stem cells such as bone marrow-derived mesenchymal stem cells. The expression of Oct4 is down-regulated coincident with stem cell differentiation and loss of expression leading to differentiation. It plays a critical role for maintaining pluripotency and self-renewal of embryonic stem cells. However, the usefulness of Oct4 as a pluripotency marker was challenged recently. More and more data seem to support that Oct4 is expressed on a variety of differentiated cells, including peripheral blood mononuclear cells. Taking into account that RT-PCR can potentially generate experimental artifacts due to pseudogene transcripts, the existence of Oct4 pseudogenes should be investigated further here. Suo et al. were able to detect transcription of some Oct4 pseudogenes in cancer cell lines as well as cancer tissues. These results show that some of the known Oct4 pseudogenes are transcribed in vivo and therefore could lead to RT-PCR artifacts. However this known problem was not seriously taken into consideration in recent publications on adult stem cells and tissue analysis referring to Oct4. We started with an initial alignment of Oct4 compared to its alternative splice variants as well as its pseudogenes. This alignment served as a prerequisite for an exact primer design. First the sequence and organization of the functional human Oct4 gene were clarified to allow comparison to the pseudogenes and alternatively spliced transcripts. The NCBI human EST database was searched and the UniGene cluster for Oct4 (NM_002701) examined. This yielded 13 mRNA sequences and 129 EST sequences. An additional BLASTn search of the human genome using single exons of Oct4 revealed several other highly similar sequences. All these hits encoded complete or partial Oct4 sequences and could therefore represent either functional members of an Oct4 gene family or pseudogenes. The fact that so many homologous sequences resemble the original Oct4 transcript makes an RT-PCR analysis difficult, because a lot of artifacts can arise during amplification. Therefore primers were designed which are able to exclude amplification of all unwanted transcripts. To conclude, based on the fact that the expression of Oct4 has been reported in adult stem cells as well as in a variety of differentiated cells the possibility cannot be excluded that the detected Oct4 signal came from alternatively spliced or Oct4 pseudogene transcripts. As shown here, an exact design of Oct4-specific primers is an inevitable prerequisite for appropriate RT-PCR analysis. In addition, a careful comparison of quantitative differences to human embryonic stem cells should be present too, before cells are described as embryonic like cells. We hope that our findings will help other stem cell researchers to find their appropriate tools especially for RT-PCR analysis and give an example how later problematic artifacts can be ruled out from the beginning by a detailed alignment as a prerequisite for designing appropriate primers.

Types of Stem Cells Used in US-Based Clinical Trials between 1999 and 2014

2021 ◽  
Vol 26 ◽  
pp. 169-191
Author(s):  
Emma E. Redfield ◽  
Erin K. Luciano ◽  
Monica J. Sewell ◽  
Lucas A. Mitzel ◽  
Isaac J. Sanford ◽  
...  
Keyword(s):  
Stem Cells ◽  
Clinical Trials ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Adult Stem Cells ◽  
Embryonic Stem ◽  
Cell Types ◽  
The Us ◽  
Health Database ◽  
Induced Pluripotent

This study looks at the number of clinical trials involving specific stem cell types. To our knowledge, this has never been done before. Stem cell clinical trials that were conducted at locations in the US and registered on the National Institutes of Health database at ‘clinicaltrials.gov’ were categorized according to the type of stem cell used (adult, cancer, embryonic, perinatal, or induced pluripotent) and the year that the trial was registered. From 1999 to 2014, there were 2,357 US stem cell clinical trials registered on ‘clinicaltrials.gov,’ and 89 percent were from adult stem cells and only 0.12 percent were from embryonic stem cells. This study concludes that embryonic stem cells should no longer be used for clinical study because of their irrelevance, moral questions, and induced pluripotent stem cells.

scholarly journals Regulation of Prostatic Stem Cells by Stromal Niche in Health and Disease

Endocrinology ◽  
2008 ◽  
Vol 149 (9) ◽  
pp. 4303-4306 ◽  
Author(s):  
Gail P. Risbridger ◽  
Renea A. Taylor
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Adult Stem Cells ◽  
Embryonic Stem ◽  
Tumor Stroma ◽  
Stem Cell Differentiation ◽  
Stem Cell Regulation ◽  
Isolation And Characterization ◽  
Tissue Recombination ◽  
Cell Niche

The isolation and characterization of prostatic stem cells has received significant attention in the last few years based on the belief that aberrant regulation of adult stem cells leads to prostate disease including cancer. The nature of the perturbations in stem cell regulation remains largely unknown. Although adult stem cells are can be governed by autonomous regulatory mechanisms, the stromal niche environment also provides essential cues to direct directing differentiation decisions and can lead to aberrant proliferation and/or differentiation. Elegant tissue recombination experiments, pioneered by Gerald Cunha and colleagues, provided evidence that quiescent epithelial tissues containing adult stem cells were capable of altered differentiation in response to inductive and instructive mesenchyme. In more recent times, it has been demonstrated that embryonic mesenchyme is sufficiently powerful to direct the differentiation of embryonic stem cells into mature prostate or bladder. In addition, prostatic tumor stroma provides another unique niche or microenvironment for stem cell differentiation that is distinct to normal stroma. This review highlights the importance of the appropriate selection of the stromal cell niche for tissue regeneration and implies plasticity of adult stem cells that is dictated by the tissue microenvironment.

scholarly journals Stem Cell and Markers

2019 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Adult Stem Cells ◽  
Inner Cell Mass ◽  
Cell Mass ◽  
Embryonic Stem ◽  
Stem Cell Markers ◽  
Cell Markers ◽  
Wide Range

Stem cells have the ability to go through various cell divisions and also maintain undifferentiated state. Stem cells are Embryonic (Pluripotent) and adult stem cells. Pluripotent stem cells give rise to all tissues such as ectoderm, mesoderm and endoderm. Embryonic stem cells isolated from inner cell mass of embryo blastocyst. Adult stem cells are also undifferentiated cells present in adult organisms and repair the tissue when damaged occurs but number in less. Adult stem cells are present in bone marrow, adipose tissue, blood and juvenile state umbilical cord and tissue of specific origin like liver, heart, intestine and neural tissue. Embryonic stem cells from blastocyst have the ethical problems and tumorogenecity. These can be identified by flow cytometry. There are wide range of stem cell markers which are useful in identifying them. Most of the pluripotent cell markers are common with tumor cell markers which throws a challenge for certainty.

scholarly journals Stem Cells: Insights into Niche, Classification, Identification, Characterization, Mechanisms of Regeneration by Using Stem Cells, and Applications in Joint Disease Remedy

2021 ◽  
Vol 2 (1) ◽  
pp. 01-07
Author(s):  
Azab Azab
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Immunosuppressive Therapy ◽  
Adult Stem Cells ◽  
Embryonic Stem ◽  
Joint Disease ◽  
Cartilage Defects ◽  
Germ Layers ◽  
Fetal Stem Cells

Background: Stem cell therapy has attracted much interest in the 21st century, not only because of the controversy surrounding the ethics involving pluripotent stem cells, but their potential for clinical use. Objectives: The present review highlights the stem cells niche, types, identification, and characterization, mechanisms of regeneration by using stem cells, and applications in joint disease remedy. Stem cells could be well differentiated cells with the potential to display different cell types depending on the host niche. Niche is defined as the cellular microenvironment providing support and stimuli to control the properties of stem cells. It consists of signaling molecules, inter-cell contacts and interaction between stem cells and their extracellular matrix neighbors. Stem cells are classified according to their sources into two main types, the embryonic and non-embryonic. Embryonic stem cells are pluripotent and can differentiate into all germ layers. Non-embryonic stem cells can be sub-classified into fetal stem cells and adult stem cells. Cultured cells can be made to differentiate into exclusive lineages by providing selective media components that can be identified by histochemical staining and quantified by quantitative Real-time polymerase chain reaction. Mesenchymal stem cells (MSCs) can be identified based on the expression of specific proteins called surface antigen phenotype of mesenchymal stem cell markers. MSCs secrete a variety of interleukins, several neurotrophic factors, many cytokines, and growth factors. These secreted bioactive factors have both paracrine and autocrine effects, which are anti-fibrotic and anti-apoptotic, as well as enhance angiogenesis. Furthermore, they stimulate mitosis and differentiation of tissue-intrinsic reparative stem cells. Systemic MSC transplantation can engraft to an injured tissue and promote wound healing through differentiation, and proliferation in synergy with hematopoietic stem cells. MSCs have been shown to express a variety of chemokines and chemokine receptors and can home to sites of inflammation by migrating towards injury or inflammatory chemokines and cytokines. MSCs are proven to have immunomodulatory properties that are among the most intriguing aspects of their biology. The immunosuppressive properties of MSCs inhibit the immune response of naive and memory T cells in a mixed lymphocyte culture and induce mitogen. The systemic infusion of MSCs can be used in immunosuppressive therapy of various disorders. MSCs have become an alternative source of cells that can be drawn from several these cells have been used as treatment to repair cartilage defects at early stages sources. Using the MSCs and directing them into chondrogenic differentiation might lead to the formation of higher quality cartilage, which has a great composition of hyaline, adequate structural reorganization and therefore improved biomechanical properties. Conclusion: It can be concluded that stem cells are classified according to their sources into two main types, the embryonic and non-embryonic. Embryonic stem cells are pluripotent and can differentiate into all germ layers. Non-embryonic stem cells can be sub-classified into fetal stem cells and adult stem cells. MSCs secrete bioactive factors that are anti-fibrotic and anti-apoptotic, as well as enhance angiogenesis. The systemic infusion of MSCs can be used in immunosuppressive therapy of various disorders. These cells have been used as treatment to repair cartilage defects at early stages.

scholarly journals Embryos, Clones, and Stem Cells: A Scientific Primer

2004 ◽  
Vol 4 ◽  
pp. 662-715 ◽  
Author(s):  
Kenyon S. Tweedell
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Cell Lines ◽  
Human Embryonic Stem Cells ◽  
Adult Stem Cells ◽  
Embryonic Stem ◽  
Normal Function ◽  
Cell Recovery ◽  
Stem Cell Lines

This article is intended to give the nonspecialist an insight into the nuances of “clones”, cloning, and stem cells. It distinguishes embryonic and adult stem cells, their normal function in the organism, their origin, and how they are recovered to produce stem cell lines in culture. As background, the fundamental processes of embryo development are reviewed and defined, since the manipulation of stem cell lines into desired specialized cells employs many of the same events. Stem cells are defined and characterized and shown how they function in the intact organism during early development and later during cell regeneration in the adult. The complexity of stem cell recovery and their manipulation into specific cells and tissue is illustrated by reviewing current experimentation on both embryonic and adult stem cells in animals and limited research on human stem cell lines. The current and projected use of stem cells for human diseases and repair, along with the expanding methodology for the recovery of human embryonic stem cells, is described. An assessment on the use of human embryonic stem cells is considered from ethical, legal, religious, and political viewpoints.

Long Noncoding RNA: Function and Mechanism on Differentiation of Mesenchymal Stem Cells and Embryonic Stem Cells

2019 ◽  
Vol 14 (3) ◽  
pp. 259-267
Author(s):  
Jian Zhu ◽  
Yitian Wang ◽  
Wei Yu ◽  
Kaishun Xia ◽  
Yuluan Huang ◽  
...  
Keyword(s):  
Stem Cells ◽  
Mesenchymal Stem Cells ◽  
Stem Cell ◽  
Embryonic Stem Cells ◽  
Transcription Regulation ◽  
Noncoding Rna ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Differentiation Process ◽  
Pathologic Process

Background:Long suspected as transcriptional noise, recently recognized, long non-coding RNAs (lncRNAs) are emerging as an indicator, biomarker and therapy target in the physiologic and pathologic process. Mesenchymal stem cells and embryonic stem cells are important source for normal and therapeutic tissue repair. However, the mechanism of stem cell differentiation is not completely understood. Research on lncRNAs may provide novel insights into the mechanism of differentiation process of the stem cell which is important for the application of stem cell therapy. The lncRNAs field is still very young, new insights into lncRNAs function are emerging to a greater understanding of biological processes. Objective: In this review, we summarize the recent researches studying lncRNAs and illustrate how they act in the differentiation of the mesenchymal stem cells and embryonic stem cells, and discuss some future directions in this field. Results: Numerous lncRNAs were differentially expressed during differentiation of mesenchymal stem cells and embryonic stem cells. LncRNAs were able to regulate the differentiation processes through epigenetic regulation, transcription regulation and post-transcription regulation. Conclusion: LncRNAs are involved in the differentiation process of mesenchymal stem cells and embryonic stem cells, and they could become promising indicator, biomarker and therapeutic targets in the physiologic and pathologic process. However, the mechanisms of the role of lncRNAs still require further investigation.

scholarly journals A Case of Identity: HOX Genes in Normal and Cancer Stem Cells

Cancers ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 512 ◽  
Author(s):  
Smith ◽  
Zyoud ◽  
Allegrucci
Keyword(s):  
Stem Cells ◽  
Stem Cell ◽  
Cell Differentiation ◽  
Cancer Stem Cells ◽  
Adult Stem Cells ◽  
Hox Genes ◽  
Embryonic Stem ◽  
Stem Cell Differentiation ◽  
Embryonic Stem Cell Differentiation ◽  
Hox Gene

Stem cells are undifferentiated cells that have the unique ability to self-renew and differentiate into many different cell types. Their function is controlled by core gene networks whose misregulation can result in aberrant stem cell function and defects of regeneration or neoplasia. HOX genes are master regulators of cell identity and cell fate during embryonic development. They play a crucial role in embryonic stem cell differentiation into specific lineages and their expression is maintained in adult stem cells along differentiation hierarchies. Aberrant HOX gene expression is found in several cancers where they can function as either oncogenes by sustaining cell proliferation or tumor-suppressor genes by controlling cell differentiation. Emerging evidence shows that abnormal expression of HOX genes is involved in the transformation of adult stem cells into cancer stem cells. Cancer stem cells have been identified in most malignancies and proved to be responsible for cancer initiation, recurrence, and metastasis. In this review, we consider the role of HOX genes in normal and cancer stem cells and discuss how the modulation of HOX gene function could lead to the development of novel therapeutic strategies that target cancer stem cells to halt tumor initiation, progression, and resistance to treatment.

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