Showing papers by "Peter W. Andrews published in 2002"

Surface antigens of human embryonic stem cells: changes upon differentiation in culture.

Abstract: We have analysed the surface antigen phenotype of a human embryonic stem (hES) cell line (H7) and the changes that occur upon differentiation induced by retinoic acid, hexamethylene bisacetamide and dimethylsulphoxide. The undifferentiated stem cells expressed Stage Specific Embryonic Antigen-3 (SSEA3), SSEA4, TRA-1-60, and TRA-1-8 but not SSEA1. In these characteristics they closely resemble human embryonal carcinoma (EC) cells derived from testicular teratocarcinomas, and are distinct from murine EC and ES cells. The undifferentiated cells also expressed the liver/bone/kidney isozyme of alkaline phosphatase detected by antibody TRA-2-54, the class 1 major histocompatability antigens, HLA-ABC, and the human Thy1 antigen. Differentiation of hES cells was induced by retinoic acid, HMBA and DMSO with the appearance of various cell types including neurons and muscle cells. The surface antigens characteristically expressed by hES cells were down-regulated following induction of differentiation and other antigens appeared, notably several ganglioside glycolipids detected by antibodies VIN-IS-56 (GD3 and GD2), VIN-2PB-22 (GD2), A2B5 (GT3) and ME311 (9-O-acetyl-GD3). Whereas the expression of HLA was slightly down-regulated upon differentiation, its expression was strongly induced by interferon-γ in both the undifferentiated and the differentiated cells, although the induction in the differentiated cultures was considerably stronger than in the stem cells. In all of these features the human ES cells, and their pattern of differentiation, resembled the pluripotent human EC cell line NTERA-2 although clearly the range of cells generated by the hES cells was considerably greater.

Preimplantation Human Embryos and Embryonic Stem Cells Show Comparable Expression of Stage‐Specific Embryonic Antigens

Abstract: Cell-surface antigens provide invaluable tools for the identification of cells and for the analysis of cell differentiation. In particular, stage-specific embryonic antigens that are developmentally regulated during early embryogenesis are widely used as markers to monitor the differentiation of both mouse and human embryonic stem (ES) cells and their malignant counterparts, embryonic carcinoma (EC) cells. However, there are notable differences in the expression patterns of some such markers between human and mouse ES/EC cells, and hitherto it has been unclear whether this indicates significant differences between human and mouse embryos, or whether ES/EC cells correspond to distinct cell types within the early embryos of each species. We now show that human ES cells are characterized by the expression of the cell-surface antigens, SSEA3, SSEA4, TRA-1-60, and TRA-1-81, and by the lack of SSEA1, and that inner cell mass cells of the human blastocyst express a similar antigen profile, in contrast to the corresponding cells of the mouse embryo.

From teratocarcinomas to embryonic stem cells

Abstract: The recent derivation of human embryonic stem (ES) cell lines, together with results suggesting an unexpected degree of plasticity in later, seemingly more restricted, stem cells (so-called adult stem cells), have combined to focus attention on new opportunities for regenerative medicine, as well as for understanding basic aspects of embryonic development and diseases such as cancer. Many of the ideas that are now discussed have a long history and much has been underpinned by the earlier studies of teratocarcinomas, and their embryonal carcinoma (EC) stem cells, which present a malignant surrogate for the normal stem cells of the early embryo. Nevertheless, although the potential of EC and ES cells to differentiate into a wide range of tissues is now well attested, little is understood of the key regulatory mechanisms that control their differentiation. Apart from the intrinsic biological interest in elucidating these mechanisms, a clear understanding of the molecular process involved will be essential if the clinical potential of these cells is to be realized. The recent observations of stem-cell plasticity suggest that perhaps our current concepts about the operation of cell regulatory pathways are inadequate, and that new approaches for analysing complex regulatory networks will be essential.

Embryonic stem cells: advances toward potential therapeutic use.

Abstract: Established lines of human pluripotent stem cells provide a convenient tool for investigating cell differentiation in a way that is pertinent to human embryonic development, providing insights into the causes of birth defects and diseases such as cancer that involve aberrant cell proliferation and differentiation. In principle, human pluripotent stem cells, including embryonic stem and embryonic germ cells, are capable of differentiating into all of the cell types that are present in the adult human. They therefore have the potential to provide a source of tissues for replacement in diseases in which native cell types are inactivated or destroyed. Intense media and public interest has surrounded the announcement of human pluripotent stem cells derivation, focusing on the ethical implications of embryo-related work and on the prospects of an unlimited source of tissues for transplantation-based treatments. Recent studies have focused on identifying method for culture of these cells and inducing their differentiation into specific cell types.

Fusion of cells

Abstract: The invention provides in one aspect a method of producing a fused cell, comprising the steps of providing a porous filter, allowing parent cells to attach to either side of the porous filter, and causing fusion of the cell membranes through the pores of the porous filter so that the cytoplasms of the cells are contiguous through the porous filter whilst the chromosomes or nuclei of the parent cells remain separated by the porous filter. The invention also provides cells derived from fused cells, and compositions and tissues comprising cells derived from fused cells.

Human embryonic stem cells: prospects for human health - a 1-day international symposium held at the University of Sheffield.

Abstract: The recent derivation of embryonic stem cell (ES) lines from human embryos at the blastocyst stage, first by Thomson et al. (1998) in Wisconsin, and then by Reubinof et al. (2000) in Melbourne and Singapore, has led to much public discussion of ‘stem cell biology’ and ‘regenerative medicine’. The new cell lines promise to provide important new tools, not only for investigating the molecular processes that guide human development, and the causes of infertility and birth defects that arise when those mechanisms operate incorrectly, but also for providing a wide range of ‘normal’ differentiated cell types for tissue replacement therapy and drug discovery. A recent 1-day international symposium, sponsored by the Anatomical Society of Great Britain and Ireland, and hosted by the School of Medicine and Biomedical Science of the University of Sheffield, brought together several groups currently studying the biology of ES cells and their potential use in human medicine. The following collection of papers covers many of the topics discussed at that meeting.

A Notch-related Gene Located on the Long Arm of Human Chromosome 12

Abstract: Family and cytogenetic studies of testicular germ cell tumours (TGCT) suggest a strong genetic component in the aetiology of these tumours. We have focused upon genes that may play a key regulatory role in the development of germ cells. Following studies in the nematode worm, Caenorhabditis elegans [1], we have investigated the Notch gene family. Initial results indicate that members of the Notch family are expressed by primordial germ cells, and by seminoma and intratubular germ cell neoplasia, consistent with a possible role in tumour development (unpublished results).