David Hudson

Proliferative Heterogeneity in the Human Prostate: Evidence for Epithelial Stem Cells

Clonal analysis of human prostate epithelial cells was undertaken in order to identify stem cells. Two types of colony were distinguished, termed type I and type II. Type I colonies were relatively small and irregular and contained a loose mixture of differentiated and undifferentiated cells. In contrast, type II colonies were large, round, and homogeneous, consisting almost exclusively of small undifferentiated and dividing cells. The colony-forming efficiency was 5.8% ± 1.8 for freshly isolated epithelial cells. There were approximately 10 times as many type I as type II colonies and about 1 in 200 of the plated cells was capable of forming a type II colony. In three-dimensional culture on Matrigel, the type II colonies produced structures reminiscent of prostate epithelium, with luminal cells expressing markers of prostate epithelial differentiation, including the androgen receptor. On the basis of their proliferative characteristics and pluripotency, the type II colonies may be the progeny of stem cells and the type I colonies of a more differentiated transit-amplifying population.

Epithelial Cell Differentiation Pathways in the Human Prostate: Identification of Intermediate Phenotypes by Keratin Expression

SUMMARY The prostate grows slowly throughout adult life, leading to benign prostatic hyperplasia (BPH), which often results in urethral obstruction in later years. The symptoms of BPH are the second most common reason for surgery in men over 65. The aim of this study was to determine the relationship between cell proliferation and cell differentiation in BPH tissue. Using multiple antibodies, simultaneously detected with different fluorophore-conjugated secondary antibodies, several subpopulations of epithelial cells were detected. In addition to K14, basal cells also expressed keratins 15, 17, and 19 in various combinations, and some of the luminal cells also expressed K19 together with K8 and K18. Co-staining for cytokeratins and Ki-67 indicated that 44% of proliferative cells expressed K14 and 36% K19, although the difference was not statistically significant. This report provides a detailed description of the relationship between keratin expression and cell proliferation in the prostate and indicates that K19-positive cells form the link between the basal and luminal layers of the epithelium. (J Histochem Cytochem 49:271–278, 2001)

Prostate epithelial stem cells

Abstract.   The prostate gland is the site of the most commonly diagnosed cancer in men in USA and UK, accounting for one in five of new cases of male cancer. Common with many other cancer types, prostate cancer is believed to arise from a stem cell that shares characteristics with the normal stem cell. Normal prostate epithelial stem cells were recently identified and found to have a basal cell phenotype together with expression of CD133. Preliminary data have now emerged for a prostate cancer stem cell that also expresses cell surface CD133 but lacks expression of the androgen receptor. Here we examine the evidence supporting the existence of prostate cancer stem cells and discuss possible mechanisms of stem cell maintenance.

Expression profiling of CD133+ and CD133- epithelial cells from human prostate.

Recent evidence suggests that prostate stem cells in benign and tumor tissue express the cell surface marker CD133, but these cells have not been well characterized. The aim of our study was to gene expression profile CD133‐expressing cells.

Evidence Against a Major Role for Integrins in Calcium-Dependent Intercellular Adhesion of Epidermal Keratinocytes

It is well established that integrins mediate keratinocyte adhesion to extracellular matrix proteins, but, in addition, there is some evidence that they mediate intercellular adhesion. We have investigated the role of integrins in keratinocyte-keratinocyte adhesion by adding anti-integrin antibodies to cells in three assays that differ according to the calcium ion concentration of the medium, the presence or absence of an adhesive substrate (glass or tissue culture plastic) and the timing of antibody addition. As previously reported by Larjava et al., (J. Cell Biol. 110:803-815), a monoclonal antibody to the beta 1 subunit perturbed cell-cell adhesion when added to adherent monolayers in low calcium medium (0.1 mM calcium ions), but did not prevent cell-cell adhesion or stratification induced by raising the level of calcium ions to 1.8mM (the concentration in standard medium). Monoclonal antibodies to both the alpha 3 and beta 1 subunits inhibited the attachment, spreading and motility of keratinocytes in low or standard calcium medium when added at the time of plating; however, they had only a modest effect on the accumulation of cells in adherent clusters. Aggregation of keratinocytes in suspension required a calcium ion concentration of greater than 0.1mM and was not inhibited by any of a large panel of anti-integrin antibodies, including three new antibodies that recognise alpha 2 beta 1. We conclude that any inhibitory effects of individual anti-integrin antibodies on cell-cell adhesion are abrogated by a calcium ion concentration above 0.1mM and that in low calcium medium at least some of the inhibition of cell-cell adhesion is a consequence of the inhibition of cell-substrate adhesion and motility.

Altered expression of CD44 isoforms in squamous-cell carcinomas and cell lines derived from them

CD44 is a transmembrane glycoprotein that binds hyaluronan, extracellular matrix proteins and growth factors. Multiple isoforms of CD44 are generated by alternative splicing of 10 separate exons (V1–V10). Expression of the variable exons has been correlated with tumour progression and metastasis in a range of cell types. However, multiple CD44 isoforms are expressed by normal stratified squamous epithelia, such as the epidermis and the lining of the oral cavity. The purpose of our study was to examine CD44 expression in squamous‐cell carcinomas (SCC). By immunofluorescence we found reduced expression of one or more of the variant exons in a series of 13 oral SCC, with loss being most common in poorly differentiated tumours. Of the exons we examined, V3 was lost most frequently, but otherwise there was no consistent pattern as to which exons (V4/5, 6, 8) were missing. We also studied CD44 expression in a range of SCC lines, using Western blotting and semi‐quantitative RT‐PCR. All lines showed reduced expression of the terminal differentiation marker involucrin. Two lines showed selective loss of the largest forms of CD44 and one failed to express any of the variant exons. These cell lines, therefore, provide a useful experimental model with which to study the biological significance of exon loss in SCC.

TEAD1 and c-Cbl are novel prostate basal cell markers that correlate with poor clinical outcome in prostate cancer

Prostate cancer is the most frequently diagnosed male cancer, and its clinical outcome is difficult to predict. The disease may involve the inappropriate expression of genes that normally control the proliferation of epithelial cells in the basal layer and their differentiation into luminal cells. Our aim was to identify novel basal cell markers and assess their prognostic and functional significance in prostate cancer. RNA from basal and luminal cells isolated from benign tissue by immunoguided laser-capture microdissection was subjected to expression profiling. We identified 112 and 267 genes defining basal and luminal populations, respectively. The transcription factor TEAD1 and the ubiquitin ligase c-Cbl were identified as novel basal cell markers. Knockdown of either marker using siRNA in prostate cell lines led to decreased cell growth in PC3 and disrupted acinar formation in a 3D culture system of RWPE1. Analyses of prostate cancer tissue microarray staining established that increased protein levels of either marker were associated with decreased patient survival independent of other clinicopathological metrics. These data are consistent with basal features impacting on the development and clinical course of prostate cancers.

Governing the UN sustainable development goals: interactions, infrastructures, and institutions.

Three of the eight Millennium Development Goals (MDGs) concerned health. There is only one health goal in 17 proposed Sustainable Development Goals (SDGs). Critiques of the MDGs included missed opportunities to realise positive interactions between goals. Here we report on an interdisciplinary analytical review of the SDG process, in which experts in different SDG areas identified potential interactions through a series of interdisciplinary workshops. This process generated a framework that reveals potential conflicts and synergies between goals, and how their interactions might be governed.

Differential Expression of CD44 During Human Prostate Epithelial Cell Differentiation

CD44 is a polymorphic transmembrane glycoprotein that binds hyaluronan and growth factors. Multiple isoforms of the protein can be generated by alternative splicing but little is known about the expression and function of these isoforms in normal development and differentiation. We have investigated the expression of CD44 during normal prostate epithelial cell differentiation. A conditionally immortalized prostate epithelial cell line, Pre2.8, was used as a model system. These cells proliferate at 33C but at 39C stop dividing and undergo changes consistent with early stages of cell differentiation. During the differentiation of these cells, the expression of the CD44 isoform v3-v10 was upregulated. Two layers of epithelial cells can clearly be distinguished in the human prostate, a basal layer expressing keratins 5/14 and a luminal layer expressing keratins 8/18. In prostate tissue the v3-v10 isoform was found predominantly in basal cells but also in keratin 14-negative, keratin 19-positive cells intermediate between the two layers. CD44 v3-v10 was also expressed in other keratin 14-negative prostate tissues, the ejaculatory ducts and prostatic urethra. Therefore, CD44 v3-v10 may be important as a cell surface marker for differentiating cells in the prostate epithelium.

'A Mile Wide and an Inch Deep': Surveys of Public Attitudes towards Development Aid

In this article we argue that existing survey instruments used to examine public attitudes to global poverty are not fit for purpose. Surveys need to be redesigned to successfully support the threefold purpose of development education and public engagement. The core of our critique is that existing measures suffer from poor measurement validity, and fail to control for knowledge-levels or perceptions of aid effectiveness, both of which are thought to limit support. Researchers also lack understanding of the factors that motivate support for development aid in the first place. We conclude by making recommendations for future surveys of public attitudes and suggest that building support for development may require speaking to many publics as opposed the public.