Distinctive growth requirements and gene expression patterns distinguish progenitor B cells from pre-B cells.

Long-term bone marrow cultures have been useful in determining gene expression patterns in pre-B cells and in the identification of cytokines such as interleukin 7 (IL-7). We have developed a culture system to selectively grow populations of B lineage restricted progenitors (pro-B cells) from murine bone marrow. Pro-B cells do not grow in response to IL-7, Steel locus factor (SLF), or a combination of the two. c-kit, the SLF receptor, and the IL-7 receptor are both expressed by pro-B cells, indicating that the lack of response is not simply due to the absence of receptors. Furthermore, SLF is not necessary for the growth of pro-B cells since they could be expanded on a stromal line derived from Steel mice that produces no SLF. IL-7 responsiveness in pre-B cells is associated with an increase in n-myc expression and is correlated with immunoglobulin (Ig) gene rearrangements. Although members of the ets family of transcription factors and the Pim-1 kinase are expressed by pro-B cells, n-myc is not expressed. Pro-B cells maintain Ig genes in the germline configuration, which is correlated with a low level of recombination activating genes 1 and 2 (Rag-1 and 2) mRNA expression, but high expression of sterile mu and terminal deoxynucleotidyl transferase. Pro-B cells are unable to grow separated from the stromal layer by a porous membrane, indicating that stromal contact is required for growth. These results suggest that pro-B cells are dependent on alternative growth signals derived from bone marrow stroma and can be distinguished from pre-B cells by specific patterns of gene expression

Deletion within the Src homology domain 3 of Bruton's tyrosine kinase resulting in X-linked agammaglobulinemia (XLA).

The gene responsible for X-linked agammaglobulinemia (XLA) has been recently identified to code for a cytoplasmic tyrosine kinase (Bruton's agammaglobulinemia tyrosine kinase, BTK), required for normal B cell development. BTK, like many other cytoplasmic tyrosine kinases, contains Src homology domains (SH2 and SH3), and catalytic kinase domain. SH3 domains are important for the targeting of signaling molecules to specific subcellular locations. We have identified a family with XLA whose affected members have a point mutation (g-->a) at the 5' splice site of intron 8, resulting in the skipping of coding exon 8 and loss of 21 amino acids forming the COOH-terminal portion of the BTK SH3 domain. The study of three generations within this kinship, using restriction fragment length polymorphism and DNA analysis, allowed identification of the mutant X chromosome responsible for XLA and the carrier status in this family. BTK mRNA was present in normal amounts in Epstein-Barr virus-induced B lymphoblastoid cell lines established from affected family members. Although the SH3 deletion did not alter BTK protein stability and kinase activity of the truncated BTK protein was normal, the affected patients nevertheless have a severe B cell defect characteristic for XLA. The mutant protein was modeled using the normal BTK SH3 domain. The deletion results in loss of two COOH-terminal beta strands containing several residues critical for the formation of the putative SH3 ligand-binding pocket. We predict that, as a result, one or more crucial SH3 binding proteins fail to interact with BTK, interrupting the cytoplasmic signal transduction process required for B cell differentiation

Enhanced progression of human prostate cancer PC3 cells induced by the microenvironment of the seminal vesicle

The objective of this study was to characterise the mechanism mediating the prostate cancer progression induced by the microenvironment of seminal vesicle (SV). The invasive potential of PC3 cells significantly increased after treatment with extract from SV of NOD/SCID mouse. Among several growth factors and cytokines that were present in the SV extract, transforming growth factor-β1 (TGF-β1) significantly enhanced the invasive potential of PC3 cells; however, the additional treatment with neutralising antibody against TGF-β1 suppressed the enhanced invasive potential induced by the SV extract. Changes in the invasive potential in PC3 cells after treatment with the SV extract and/or TGF-β1 were in proportion to those in the production of urokinase-type plasminogen activator (uPA) by PC3 cells. Tumour growth as well as the incidence of lymph node metastasis in NOD/SCID mice after the injection of PC3 cells into the SV were significantly greater than those after the injection into the prostate. These findings suggest that the microenvironment of SV enhances the progression of prostate cancer through a stimulated invasive potential, and that enhanced uPA production in prostate cancer cells induced by TGF-β1 could therefore be one of the most important mechanisms involved in the progression of prostate cancer after SV invasion

Growth delay of human bladder cancer cells by Prostate Stem Cell Antigen downregulation is associated with activation of immune signaling pathways

<p>Abstract</p> <p>Background</p> <p>Prostate stem cell antigen (PSCA) is a glycosylphosphatidylinositol (GPI) anchored protein expressed not only in prostate but also in pancreas and bladder cancer as shown by immunohistochemistry and mRNA analysis. It has been targeted by monoclonal antibodies in preclinical animal models and more recently in a clinical trial in prostate cancer patients. The biological role played in tumor growth is presently unknown. In this report we have characterized the contribution of PSCA expression to tumor growth.</p> <p>Methods</p> <p>A bladder cell line was engineered to express a doxycycline (dox) regulated shRNA against PSCA. To shed light on the PSCA biological role in tumor growth, microarray analysis was carried out as a function of PSCA expression. Expression of gene set of interest was further analyzed by qPCR</p> <p>Results</p> <p>Down regulation of the PSCA expression was associated with reduced cell proliferation <it>in vitro </it>and <it>in vivo</it>. Mice bearing subcutaneous tumors showed a reduced tumor growth upon treatment with dox, which effectively induced shRNA against PSCA as revealed by GFP expression. Pathway analysis of deregulated genes suggests a statistical significant association between PSCA downregulation and activation of genes downstream of the IFNα/β receptor.</p> <p>Conclusions</p> <p>These experiments established for the first time a correlation between the level of PSCA expression and tumor growth and suggest a role of PSCA in counteracting the natural immune response.</p

Positive and Negative Regulation of Prostate Stem Cell Antigen Expression by Yin Yang 1 in Prostate Epithelial Cell Lines

Prostate cancer is influenced by epigenetic modification of genes involved in cancer development and progression. Increased expression of Prostate Stem Cell Antigen (PSCA) is correlated with development of malignant human prostate cancer, while studies in mouse models suggest that decreased PSCA levels promote prostate cancer metastasis. These studies suggest that PSCA has context-dependent functions, and could be differentially regulated during tumor progression. In the present study, we identified the multi-functional transcription factor Yin Yang 1 (YY1) as a modulator of PSCA expression in prostate epithelial cell lines. Increased YY1 levels are observed in prostatic intraepithelial neoplasia (PIN) and advanced disease. We show that androgen-mediated up-regulation of PSCA in prostate epithelial cell lines is dependent on YY1. We identified two direct YY1 binding sites within the PSCA promoter, and showed that the upstream site inhibited, while the downstream site, proximal to the androgen-responsive element, stimulated PSCA promoter activity. Thus, changes in PSCA expression levels in prostate cancer may at least partly be affected by cellular levels of YY1. Our results also suggest multiple roles for YY1 in prostate cancer which may contribute to disease progression by modulation of genes such as PSCA

Phrase Frequency Effects in Language Production

A classic debate in the psychology of language concerns the question of the grain-size of the linguistic information that is stored in memory. One view is that only morphologically simple forms are stored (e.g., ‘car’, ‘red’), and that more complex forms of language such as multi-word phrases (e.g., ‘red car’) are generated on-line from the simple forms. In two experiments we tested this view. In Experiment 1, participants produced noun+adjective and noun+noun phrases that were elicited by experimental displays consisting of colored line drawings and two superimposed line drawings. In Experiment 2, participants produced noun+adjective and determiner+noun+adjective utterances elicited by colored line drawings. In both experiments, naming latencies decreased with increasing frequency of the multi-word phrase, and were unaffected by the frequency of the object name in the utterance. These results suggest that the language system is sensitive to the distribution of linguistic information at grain-sizes beyond individual words

Behavioural plasticity in Argyrodes antipodiana.

In this thesis I look at the behavioural plasticity of A.antipodiana while foraging and interacting with conspecifics. The aim is to see how an animal, with apparently limited intelligence is able to deal with environmental variability. I conclude that A.antipodiana appears to have been able to overcome these limitations very effectively by using four methods, of which the first two effectively reduce the amount of learning necessary. Firstly, A.antipodiana simplifies the situation as much as possible by ignoring some of the variability. For example, in social situations, A.antipodiana appears to recognize only a few categories of conspecifics, rather than recognize conspecifics as individuals. Consequently, the social groups of A.antipodiana are not characterized by complicating factors such as aggressive orders or dominance hierarchies. Secondly, A.antipodiana largely ignores current situations and instead bases much of its behavioural decisions on its internal conditions. For example, in male-male conflicts, males respond to their opponents largely according to their own size, level of hunger, the number of contests in which they have participated, or their past experience of winning or losing; rather than to the characteristics of their opponents. Likewise in social interactions A.antipodiana is more inclined to be aggressive towards conspecifics if it itself is foraging, and less inclined if it is feeding with the host. When the situation cannot be simplified, A.antipodiana adopts a third response which is to use the simplest method possible for adjusting its behaviour. For example, A.antipodiana's ability to develop araneophagic skills appears to be governed by a critical period. Thus rather than developing araneophagic skills through trial and error with practise, the ability appears to be simply 'switched on' if required. The fourth means by which A.antipodiana compensates for limited intelligence is to be very selective in the areas in which it does use learning. For example, A.antipodiana seems to use problem solving when foraging, but only when it is actually trying to reach the food bundle upon which the host is feeding. A.antipodiana also seems to learn to move more stealthfully on the host's web. There is even evidence that A.antipodiana may behave with intent when males are competing for opportunities to copulate. Thus the intelligence of A.antipodiana appears to be severely limited. However, despite these limitations, by reducing the amount of learning necessary, and then channelling what learning it has to very restricted, but very poignant areas of its behaviour, A.antipodiana, is able to respond very effectively to its variable environment