Stathmin and its phosphoprotein family: general properties, biochemical and functional interaction with tubulin.

Stathmin, also referred to as Op18, is a ubiquitous cytosolic phosphoprotein, proposed to be a small regulatory protein and a relay integrating diverse intracellular signaling pathways involved in the control of cell proliferation, differentiation and activities. It interacts with several putative downstream target and/or partner proteins. One major action of stathmin is to interfere with microtubule dynamics, by inhibiting the formation of microtubules and/or favoring their depolymerization.

HCV core, NS3, NS5A and NS5B proteins modulate cell proliferation independently from p53 expression in hepatocarcinoma cell lines.

Several reports have shown that activity and/or expression of p53 can be modulated by Hepatitis C virus (HCV) proteins and may interfere with normal regulation of cell growth. In order to understand the relationship between p53 function and HCV proteins expression, we have investigated potential effects of the core, NS3, NS5A and NS5B proteins on Huh-7 (p53 +/+) and Hep3B (p53 -/-) cell proliferation. The effect of HCV proteins transiently expressed after recombinant-adenoviral infection was analyzed by Western blot, crystal violet and propidium iodide staining.

Microarray analysis reveals complex remodeling of cardiac ion channel expression with altered thyroid status: relation to cellular and integrated electrophysiology.

Although electrophysiological remodeling occurs in various myocardial diseases, the underlying molecular mechanisms are poorly understood. cDNA microarrays containing probes for a large population of mouse genes encoding ion channel subunits ("IonChips") were developed and exploited to investigate remodeling of ion channel transcripts associated with altered thyroid status in adult mouse ventricle. Functional consequences of hypo- and hyperthyroidism were evaluated with patch-clamp and ECG recordings.

The 4 A X-ray structure of a tubulin:stathmin-like domain complex.

Phosphoproteins of the stathmin family interact with the alphabeta tubulin heterodimer (tubulin) and hence interfere with microtubule dynamics. The structure of the complex of GDP-tubulin with the stathmin-like domain of the neural protein RB3 reveals a head-to-tail assembly of two tubulins with a 91-residue RB3 alpha helix in which each copy of an internal duplicated sequence interacts with a different tubulin. As a result of the relative orientations adopted by tubulins and by their alpha and beta subunits, the tubulin:RB3 complex forms a curved structure.

Butyrate and trichostatin A effects on the proliferation/differentiation of human intestinal epithelial cells: induction of cyclin D3 and p21 expression.

Background: Sodium butyrate, a product of colonic bacterial fermentation, is able to inhibit cell proliferation and to stimulate cell differentiation of colonic epithelial cell lines. It has been proposed that these cellular effects could be linked to its ability to cause hyperacetylation of histone through the inhibition of histone deacetylase.

Aim: To analyse the molecular mechanisms of butyrate action on cell proliferation/differentiation and to compare them with those of trichostatin A, a well known inhibitor of histone deacetylase.

Probing the native structure of stathmin and its interaction domains with tubulin. Combined use of limited proteolysis, size exclusion chromatography, and mass spectrometry.

Stathmin is a cytosoluble phosphoprotein proposed to be a regulatory relay integrating diverse intracellular signaling pathway. Its interaction with tubulin modulates microtubule dynamics by destabilization of assembled microtubules or inhibition of their polymerization from free tubulin. The aim of this study was to probe the native structure of stathmin and to delineate its minimal region able to interact with tubulin.

Subtractive hybridization and differential screening identified two genes differentially expressed after induction of in vitro (atypical) terminal differentiation in the NSCLC-N6 cell line by a marine substance (bistramide K).

Non-small-cell lung carcinoma is generally refractory to chemotherapy. The difficulties that arise in the treatment of this type of tumor make it necessary to develop new therapeutic strategies. Previous work done in our laboratory showed that a marine substance named bistramide K induced in vitro (atypical) terminal differentiation of NSCLC-N6 cell line.

Lack of interleukin 10 regulation of antigen presentation-associated molecules expressed on colonic epithelial cells.

Background: Colonic epithelial cells may behave as antigen-presenting cells. Interleukin 10 (IL-10) is known to play a major role in the intestinal immune system; however, it remains to be determined whether human intestinal epithelial cells express IL-10 receptor, and whether this cytokine modulates their expression of antigen presentation-associated molecules.

Methods: The binding of biotinylated IL-10 was studied in SW 1116, HT-29 and T84 human colonic epithelial cell lines and freshly isolated normal colonic epithelial cells.

Cloning of a human cancer cell line (NSCLC-N6) and comparative study of the clones in vitro.

Non-small-cell lung carcinoma (NSCLC) is a particularly serious disease because of its chemoresistance to current treatments. To investigate the nature of his generally innate resistance, we cloned an established cell line (NSCLC-N6) derived from a non-small cell bronchopulmonary carcinoma. Four cell subpopulations (C15, C65, C92 and C98) were isolated from the mother line.

Correlation between multidrug resistance and the degree of differentiation of non-small-cell bronchopulmonary carcinoma (NSCLC) in vitro and in vivo.

The correlation between the degree of expression of the multidrug resistance-1 (MDR-1) gene and the process of differentiation into non-small-cell, bronchopulmonary carcinoma was studied in vitro and in vivo. For this purpose, a technique for the quantitative analysis of MDR-1 gene expression was developed by competitive reverse-transcriptase polymerase chain reaction. The study of 9 epidermoid carcinomas with various degrees of differentiation did not enable us to establish a correlation in vivo in the patient.

Comparison of the effect of different short chain fatty acids on the growth and differentiation of human colonic carcinoma cell lines in vitro.

The aim of this study was to compare the effects of acetate, propionate, butyrate, iso-butyrate, valerate, iso-valerate and caproate on cell growth and on the activities of alkaline phosphatase (AP) and dipeptidyl aminopeptidase IV (DPP IV) by three human colonic adenocarcinoma cell lines. In addition to butyrate, propionate and valerate inhibited cell proliferation of the three cell lines. The other SCFAs did not influence cell proliferation.

Butyrate stimulates cyclin D and p21 and inhibits cyclin-dependent kinase 2 expression in HT-29 colonic epithelial cells.

Sodium butyrate, a product of colonic fermentation of dietary fiber, has been shown to inhibit cell proliferation by blocking the cells in the G1 phase of the cell cycle. However, its mechanism of action is still unknown. We found that butyrate strongly stimulated cyclin D and p21/WAF1/CIP1 expression in HT-29 human colonic adenocarcinoma cells, in a dose dependent manner.

Butyrate enhances major histocompatibility complex class I, HLA-DR and ICAM-1 antigen expression on differentiated human intestinal epithelial cells.

Besides its metabolic role, butyrate, a by-product of colonic fermentation, can modulate colonocyte proliferation and the expression of various molecules. In inflammatory bowel diseases, epithelial cells express HLA class II molecules and may behave as antigen-presenting cells. This study was performed to characterize the effect of butyrate on major histocompatibility complex expression by human colonocytes in comparison with interferon-gamma.

Antitumor and antiproliferative effects of a fucan extracted from ascophyllum nodosum against a non-small-cell bronchopulmonary carcinoma line.

Fucans, sulfated polysaccharides extracted from brown seaweeds, have been shown to be endowed with inhibitory effects cell growth in various experimental models. We studied both the antiproliferative and antitumor properties of a fucoidan extract (HF) obtained from the brown seaweed Ascophyllum nodosum on a cell line derived from a non-small-cell human bronchopulmonary carcinoma (NSCLC-N6), this type of carcinoma is particularly chemo-resistant. HF exerts in vitro a reversible antiproliferative activity with a block observed in the G1 phase the cell cycle.

Measurement of mevalonic acid in human urine by bench top gas chromatography-mass spectrometry.

Urinary excretion of mevalonate was reported to be correlated with endogenous cholesterol biosynthesis. A method is described whereby mevalonate (MVA) concentration in urine is determined by bench top gas chromatography-mass spectrometry after extraction as mevalonalactone (MVL) and conversion to mevalonolactone mono-TMS derivative. Within- and between-assay coefficients of variation were 4.