Several lines of evidence suggest that dendritic cells (DCs),Herpes simplex virus (HSV) belongs to the Herpesviridiae family, which have the characteristic ability to establish latency after primary infection, and thus to persist in the human host for life. For a virus to do so, it must be able to avoid immune eradication both after primary infection and after subsequent reactivation.Although the importance of innate immunity in HSV infection has been well characterized [1], it is the degree of adaptive immunity that best correlates with the severity of consequent clinical disease. Cellular immune

Herpes simplex virus (HSV) infects dendritic cells (DC

In breast cancer, overexpression of the small heat shock protein, HSP-27, is associated with increased anchorage-independent growth, increased invasiveness, and resistance to chemotherapeutic drugs and is associated with poor prognosis and reduced disease-free survival. Therefore, factors that increase the expression of HSP-27 in breast cancer are likely to affect the prognosis and outcome of treatment. In this study, we show a strong correlation between elevated levels of the Brn-3b POU transcription factor and high levels of HSP-27 protein in manipulated MCF-7 breast cancer cells as well as in human breast biopsies. Conversely, HSP-27 is decreased on loss of Brn-3b. In cotransfection assays, Brn-3b can strongly transactivate the HSP-27 promoter, supporting a role for direct regulation of HSP-27 expression. Brn-3b also cooperates with the estrogen receptor (ER) to facilitate maximal stimulation of the HSP-27 promoter, with significantly enhanced activity of this promoter observed on coexpression of Brn-3b and ER compared with either alone. RNA interference and site-directed mutagenesis support the requirement for the Brn-3b binding site on the HSP-27 promoter, which facilitates maximal transactivation either alone or on interaction with the ER. Chromatin immunoprecipitation provides evidence for association of Brn-3b with the HSP-27 promoter in the intact cell. Thus, Brn-3b can, directly and indirectly (via interaction with the ER), activate HSP-27 expression, and this may represent one mechanism by which Brn-3b mediates its effects in breast cancer cells.

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Brn-3b transcription factor enhances proliferation of neuroblastoma (NB) and breast cancer cell lines in vitro and increases the rate and size of in vivo tumour growth, whereas reducing Brn-3b slows growth, both in vitro and in vivo. Brn-3b is elevated in >65% of breast cancer biopsies, and here we demonstrate that Brn-3b is also elevated in NB tumours. We show a significant correlation between Brn-3b and cyclin D1 (CD1) in breast cancers and NB tumours and cell lines. Brn-3b directly transactivates the CD1 promoter in co-transfection experiments, whereas electrophoretic mobility shift assay and chromatin immunoprecipitation assays demonstrate that Brn-3b protein binds to an octamer sequence located in the proximal CD1 promoter. Site-directed mutagenesis of this sequence resulted in loss of transactivation of the CD1 promoter by Brn-3b. Thus, Brn-3b may act to alter growth properties of breast cancer and NB cells by enhancing CD1 expression in these cells.

The Brn-3b transcription factor has been shown to be overexpressed in human breast cancer cells and contributes toward cell growth regulation. Using micro-arrays, more than 50 cancerrelated genes regulated by Brn-3b in human breast cancer cells have been identified. For example, Brn-3b activates the cell cycle regulator CDK4 that provides a mechanism by which Brn-3b controls the growth of breast cancer cells. Here, we show that Brn-3b regulates plakoglobin (c-catenin), a member of the catenin family involved in cell-cell adhesion and signal transduction. Brn-3b expression inversely correlates with plakoglobin expression at both mRNA and protein levels in breast cancer cell lines and human breast biopsies. In contrast, no significant correlation was observed between Brn-3b expression and b-catenin, or between Brn-3b expression and E-cadherin expression. Brn-3b represses the plakoglobin promoter via a Brn-3 consensus binding site contained within the region 2965 to 2593 relative to the transcriptional start site. Both repression of the promoter and binding of Brn-3b are lost when this site is mutated. To our knowledge, this is the first time that a Brn-3b POU family transcription factor has been shown to regulate a member of the catenin family, which provides insight into the molecular mechanisms by which Brn-3b expression may favour breast cancer progression and tumor invasion. ' 2005 Wiley-Liss, Inc.Key words: breast cancer; metastasis; Brn-3b transcription factor; Plakoglobin (g-catenin), micro-arrayThe POU (Pit-Oct-Unc) family of transcription factors were originally identified on the basis of a common DNA binding domain, referred to as the POU domain, present in the mammalian transcription factors Pit-1, Oct-1 and Oct-2 and the nematode regulatory protein Unc-86. 1,2 A number of POU family transcription factors have been identified in the nervous system where they have been shown to play a critical role in the regulation of gene expression. Thus, the closely related POU family transcription factors Brn-3a, Brn-3b and Brn-3c were originally identified on the basis of their distinct but overlapping patterns of gene expression in the developing and adult nervous systems. [3][4][5][6] Inactivation of the individual genes encoding these factors has been shown to produce defects in the development of specific parts of the nervous system. 7-9 However, expression of Brn-3a and Brn-3b has also been observed in non-neuronal cells such as in the testis, 10 breast 11 and cervix. 4,12 Changes in expression of Brn-3a and Brn-3b have been reported in tumors derived from the cells which normally express them, suggesting a role for this family of transcription factors in cancer. Indeed, Brn-3a has been shown to be overexpressed in aggressive neuroendocrine tumors, 13 whilst Brn-3b is expressed at high levels in human neuroblastomas. 14,15 Similarly, Brn-3a is highly overexpressed in human cervical intraepithelial neoplasia grade 3 (CIN3), compared to normal human cervical samples. 12 Interestingly, our previous studies have ...

IL-2 induces growth, differentiation, and/or apoptosis of lymphoid cells. To study further the molecular basis of IL-2 function, we used a cDNA subtraction approach involving a cell line grown in IL-2 or IL-4. From the corresponding library, 66 nonredundant sequences were characterized; 16 of them encode identified proteins. The kinetics of in vitro expression of 8 selected sequences, the functions of which could be associated with IL-2-induced T cell activation/differentiation, was investigated using an IL-2-dependent T cell line. IL-2 increased the expression of cytoskeleton proteins (α-tubulin), oncogene-regulating proteins (CCCTC-binding factor, Jun inhibitor factor-1), and transcription factors (E2F-4, cyclic AMP-responsive element-binding protein, zhx-1). IL-2 also regulated the expression of genes coding for multifunctional proteins, e.g., β-catenin and nucleolin. These results were verified using Con A-induced T cell blasts stimulated or not by IL-2. The in vivo expression of four of these genes was also analyzed in spleen and lymph node cells of IL-2-deficient and MRL/lpr mice, which both have high numbers of activated cells, but the latter have intact IL-2 expression. The expression of β-catenin, CCCTC-binding factor, Jun inhibitor factor-1, and nucleolin was significantly higher in MRL/lpr animals. A similar analysis of thymocytes from IL-2−/− and IL-2+/− mice demonstrated the same expression patterns of the 4 sequences in these strains. The expression of the IL-2-induced genes described herein is similar to the regulatory pattern of IL-2Rα. Taken together, our data provide additional evidence for the pleiotropic action of IL-2 in the periphery and IL-2 independence of molecular processes involved in thymocyte differentiation.

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