Regulation of ischemic neuronal death by E2F4-p130 protein complexes.

Inappropriate activation of cell cycle proteins, in particular cyclin D/Cdk4, is implicated in neuronal death induced by various pathologic stresses, including DNA damage and ischemia. Key targets of Cdk4 in proliferating cells include members of the E2F transcription factors, which mediate the expression of cell cycle proteins as well as death-inducing genes. However, the presence of multiple E2F family members complicates our understanding of their role in death.

Immortalization of human alveolar epithelial cells to investigate nanoparticle uptake.

Primary human alveolar type 2 (AT2) cells were immortalized by transduction with the catalytic subunit of telomerase and simian virus 40 large-tumor antigen. Characterization by immunochemical and morphologic methods demonstrated an AT1-like cell phenotype. Unlike primary AT2 cells, immortalized cells no longer expressed alkaline phosphatase, pro-surfactant protein C, and thyroid transcription factor-1, but expressed increased caveolin-1 and receptor for advanced glycation end products (RAGE).

A conditionally immortalized cell line model for the study of human prostatic epithelial cell differentiation.

In the normal human prostate, undifferentiated proliferative cells reside in the basal layer and give rise to luminal secretory cells. There are, however, few epithelial cell lines that have a basal cell phenotype and are able to differentiate. We set out to develop a cell line with these characteristics that would be suitable for the study of the early stages of prostate epithelial cell differentiation.

Establishment of the epithelial-specific transcriptome of normal and malignant human breast cells based on MPSS and array expression data.

Introduction: Diverse microarray and sequencing technologies have been widely used to characterise the molecular changes in malignant epithelial cells in breast cancers. Such gene expression studies to identify markers and targets in tumour cells are, however, compromised by the cellular heterogeneity of solid breast tumours and by the lack of appropriate counterparts representing normal breast epithelial cells.

Methods: Malignant neoplastic epithelial cells from primary breast cancers and luminal and myoepithelial cells isolated from normal human breast tissue were isolated by immunomagnetic separation methods.

The Chk1/Cdc25A pathway as activators of the cell cycle in neuronal death induced by camptothecin.

Cell cycle regulators appear to play a paradoxical role in neuronal death. We have shown previously that cyclin-dependent kinases (CDKs), along with their downstream effectors, Rb (retinoblastoma) and E2F/DP1 (E2 promoter binding factor/deleted in polyposis 1), regulate neuronal death evoked by the DNA damaging agent camptothecin. However, the mechanism by which CDKs are activated in this model is unclear.

Differential roles of nuclear and cytoplasmic cyclin-dependent kinase 5 in apoptotic and excitotoxic neuronal death.

Cyclin-dependent kinase 5 (cdk5) is a member of the cyclin-dependent kinase family whose activity is localized mainly to postmitotic neurons attributable to the selective expression of its activating partners p35 and p39. Deregulation of cdk5, as a result of calpain cleavage of p35 to a smaller p25 form, has been suggested to be a central component of neuronal death underlying numerous neurodegenerative diseases. However, the relevance of cdk5 in apoptotic death that relies on the mitochondrial pathway is unknown.

Heightened expression of CTCF in breast cancer cells is associated with resistance to apoptosis.

CTCF is a candidate tumor suppressor gene encoding a multifunctional transcription factor. Surprisingly for a tumor suppressor, the levels of CTCF in breast cancer cell lines and tumors were found elevated compared with breast cell lines with finite life span and normal breast tissues. In this study, we aimed to investigate the possible cause for this increase in CTCF content and in particular to test the hypothesis that up-regulation of CTCF may be linked to resistance of breast cancer cells to apoptosis.

Cytokeratin 5/6 in normal human breast: lack of evidence for a stem cell phenotype.

In recent studies, Böcker and colleagues described a population of cells in paraffin wax sections of normal human breast that express cytokeratins (CK) 5/6 without expression of CK8/18 or smooth muscle actin (SMA). They proposed that these represent stem cells that give rise to differentiated luminal and myoepithelial cells. The data have been used to generate a model for breast cancer progression and classification with associated implications for management of pre-invasive disease.

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.

Order of genetic events is critical determinant of aberrations in chromosome count and structure.

A sequential acquisition of genetic events is critical in tumorigenesis. A key step is the attainment of infinite proliferative potential. Acquisition of this immortalization requires the activation of telomerase in addition to other activities, including inactivation of TP53 and the retinoblastoma family of tumor-suppressor proteins.

Expression profiling of purified normal human luminal and myoepithelial breast cells: identification of novel prognostic markers for breast cancer.

The normal duct-lobular system of the breast is lined by two epithelial cell types, inner luminal secretory cells and outer contractile myoepithelial cells. We have generated comprehensive expression profiles of the two normal cell types, using immunomagnetic cell separation and gene expression microarray analysis. The cell-type specificity was confirmed at the protein level by immunohistochemistry in normal breast tissue.

Nuclear factor-(kappa)B modulates the p53 response in neurons exposed to DNA damage.

Previous studies have shown that DNA damage-evoked death of primary cortical neurons occurs in a p53 and cyclin-dependent kinase-dependent (CDK) manner. The manner by which these signals modulate death is unclear. Nuclear factor-kappaB (NF-kappaB) is a group of transcription factors that potentially interact with these pathways.

Emerging pathogenic role for cyclin dependent kinases in neurodegeneration.

While the requirement of CDKs in cell cycle control is well established, the participation of CDK family members in other important biological processes are now beginning to be uncovered. Paramount in these newly defined roles is the surprising involvement of CDKs in neuronal development and death. These discoveries are somewhat of a paradox considering the terminally differentiated state of neurons.

Models of breast cancer: is merging human and animal models the future?

Survival rates of patients with early breast cancer in the United Kingdom and in the United States have improved steadily over the past 15 years. The only way to continue or even accelerate this progress, however, is the discovery and development of new preventative and therapeutic strategies. With the massive explosion in potential therapeutic strategies becoming available, in the postgenomic era, better and more representative breast cancer models are urgently required for preclinical trials.

Cyclin-dependent kinase 5 is a mediator of dopaminergic neuron loss in a mouse model of Parkinson's disease.

Recent evidence indicates that cyclin-dependent kinases (CDKs, cdks) may be inappropriately activated in several neurodegenerative conditions. Here, we report that cdk5 expression and activity are elevated after administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), a toxin that damages the nigrostriatal dopaminergic pathway. Supporting the pathogenic significance of the cdk5 alterations are the findings that the general cdk inhibitor, flavopiridol, or expression of dominant-negative cdk5, and to a lesser extent dominant-negative cdk2, attenuates the loss of dopaminergic neurons caused by MPTP.

Arylamine N-acetyltransferase-1 is highly expressed in breast cancers and conveys enhanced growth and resistance to etoposide in vitro.

Comparative two-dimensional proteome analysis was used to identify proteins differentially expressed in multiple clinical normal and breast cancer tissues. One protein, the expression of which was elevated in invasive ductal and lobular breast carcinomas when compared with normal breast tissue, was arylamine N-acetyltransferase-1 (NAT-1), a Phase II drug-metabolizing enzyme. NAT-1 overexpression in clinical breast cancers was confirmed at the mRNA level and immunohistochemical analysis of NAT-1 in 108 breast cancer donors demonstrated a strong association of NAT-1 staining with estrogen receptor-positive tumors.

Immortalisation of human ovarian surface epithelium with telomerase and temperature-sensitive SV40 large T antigen.

Epithelial ovarian cancer is the most common form of gynaecological malignancy. This lethal disease is thought to arise in ovarian surface epithelial (OSE) cells. The biology of these cells is not well understood, due to the limited amount of tissue that can be obtained from a single biopsy and their limited life span in culture.

Functional analysis of PKD1 transgenic lines reveals a direct role for polycystin-1 in mediating cell-cell adhesion.

The PKD1 protein, polycystin-1, is a large transmembrane protein of uncertain function and topology. To study the putative functions of polycystin-1, conditionally immortalized kidney cells transgenic for PKD1 were generated and an interaction between transgenic polycystin-1 and endogenous polycystin-2 has been recently demonstrated in these cells. This study provides the first functional evidence that transgenic polycystin-1 directly mediates cell-cell adhesion.

cDNA microarray analysis of genes associated with ERBB2 (HER2/neu) overexpression in human mammary luminal epithelial cells.

To investigate changes in gene expression associated with ERBB2, expression profiling of immortalized human mammary luminal epithelial cells and variants expressing a moderate and high level of ERBB2 has been carried out using cDNA microarrays corresponding to approximately 6000 unique genes/ESTs. A total of 61 significantly up- or downregulated (2.0-fold) genes were identified and further validated by RT-PCR analysis as well as microarray comparisons with a spontaneously ERBB2- overexpressing breast cancer cell line and ERBB2-positive primary breast tumors.

Comprehensive sampling of gene expression in human cell lines with massively parallel signature sequencing.

Whereas information is rapidly accumulating about the structure and position of genes encoded in the human genome, less is known about the complexity and relative abundance of their expression in individual human cells and tissues. Here, we describe the characteristics of the transcriptomes of two cultured cell lines, HB4a (normal breast epithelium) and HCT-116 (colon adenocarcinoma), using massively parallel signature sequencing (MPSS). We generated in excess of 10(7) short signature sequences per cell line, thus providing a comprehensive snapshot of gene expression, within the technical limitations of the method.

Regulation of breast cancer cell chemotaxis by the phosphoinositide 3-kinase p110delta.

Class IA phosphoinositide 3'-kinases (PI3Ks) regulate many cellular processes downstream of tyrosine kinases and Ras. Despite a clear implication of PI3K in cancer, little is known about the distribution of the different PI3K isoforms in malignant cells. We screened a large panel of tissues and cell lines for expression of class IA PI3Ks, and document a ubiquitous expression of the p110alpha and p110beta isoforms but a variable and more restricted tissue distribution of the p110delta isoform.

Cyclin-dependent kinases and stroke.

Cyclin-dependent kinases (CDKs) are a group of enzymes predominately known for their role in cell cycle regulation in proliferating cell types. Increasing evidence, however, suggests that CDKs also promote death in neurones. These observations have lead to the notion that CDKs may serve as a therapeutic target for neuropathological conditions such as stroke.

Effects of ErbB-2 overexpression on mitogenic signalling and cell cycle progression in human breast luminal epithelial cells.

Most breast cancers arise from luminal epithelial cells and 25-30% of these tumours overexpress the ErbB-2 receptor. Herein, a non-transformed, immortalized cell system was used to investigate the effects of ErbB-2 overexpression in luminal epithelial cells. The phenotypic consequence of ErbB-2 overexpression is a shortening of the G1 phase of the cell cycle and early S phase entry, which leads to hyperproliferation.

The expression patterns of integrin subunits on human breast tissues obtained during pregnancy.

Integrins have been shown to exert regulatory influences on mammary differentiation and morphogenesis in rodent experimental systems. We have, therefore, examined the expression patterns of integrin subunits on human breast tissues obtained at the 12th, 15th and 18th weeks of pregnancy. Myoepithelial cells were positive for all the integrin subunits examined.