Crosstalk between stem cell and cell cycle machineries

1. Download : Download high-res image (197KB)
2. Download : Download full-size image

     

Enteric glial cell heterogeneity regulates intestinal stem cell niches

1. Download : Download high-res image (211KB)
2. Download : Download full-size image

     

Integrated glycoproteomic characterization of clear cell renal cell carcinoma

1. Download : Download high-res image (269KB)
2. Download : Download full-size image

     

Generation of cell hybrids via a fusogenic cell line

BACKGROUND: Hybrids obtained by fusion between tumour cells (TC) and dendritic cells (DC) have been proposed as anti-tumour vaccines because of their potential to combine the expression of tumour-associated antigens with efficient antigen presentation. The classical methods used for fusion, polyethylene glycol (PEG) and electrofusion, are cytotoxic and generate cell debris that can be taken up by DC rendering the identification of true hybrids difficult. METHODS: We have established a stable cell line expressing a viral fusogenic membrane glycoprotein (FMG) that is not itself susceptible to fusion. This cell line has been used to generate hybrids and to evaluate the relevance of tools used for hybrid detection. RESULTS: This FMG-expressing cell line promotes fusion between autologous or allogeneic TC and DC in any combination, generating 'tri-parental hybrids'. At least 20% of TC are found to be integrated into hybrids. CONCLUSIONS: It is speculated that this tri-parental hybrid approach offers new possibilities to further modulate the anti-tumour effect of the DC/TC hybrids since it allows the expression of relevant immunostimulatory molecules by appropriate engineering of the fusogenic cell line.     

Intranuclear localization of proliferating cell nuclear antigen during the cell cycle in renal cell carcinoma

OBJECTIVE: To investigate, with laser scanning cytometry (LSC), proliferating cell nuclear antigen (PCNA) expression during the cell cycle in renal cell carcinoma. STUDY DESIGN: DNA ploidy and intracellular localization of PCNA in renal cell carcinoma were determined using LSC and immunohistochemistry. The subjects were nine patients who had received surgery for renal cell carcinoma. After DNA ploidy analysis, the glass slides were restained by immunohistochemistry of PCNA. LSC allowed direct observation of PCNA localization during the cell cycle because we could obtain immunohistochemical staining of PCNA as a function of cell cycle phase for individual cells. RESULTS: PCNA was not demonstrated in the nuclei of G0/G1 cells. PCNA expression increased from the S phase of the cell cycle. PCNA rapidly degraded at the end of the G2 phase. In the late G2 and M phase, PCNA was not detected in almost any nucleus. CONCLUSION: LSC allows morphologic observation of the intracellular distribution of PCNA during the cell cycle in renal cell carcinoma.     

Effect of lycopene on cell viability and cell cycle progression in human cancer cell lines

ABSTRACT: BACKGROUND: Lycopene, a major carotenoid component of tomato, has a potential anticancer activity in many types of cancer. Epidemiological and clinical trials rarely provide evidence for mechanisms of the compound's action, and studies on its effect on cancer of different cell origins are now being done. The aim of the present study was to determine the effect of lycopene on cell cycle and cell viability in eight human cancer cell lines. METHODS: Human cell lines were treated with lycopene (1-5 uM) for 48 and 96 h. Cell viability was monitored using the method of MTT. The cell cycle was analyzed by flow cytometry, and apoptotic cells were identified by terminal deoxynucleotidyl transferase-mediated dUTP nick labeling (TUNEL) and by DAPI. RESULTS: Our data showed a significant decrease in the number of viable cells in three cancer cells lines (HT-29, T84 and MCF-7) after 48 h treatment with lycopene, and changes in the fraction of cells retained in different cell cycle phases. Lycopene promoted also cell cycle arrest followed by decreased cell viability in majority of cell lines after 96 h, as compared to controls. Furthermore, an increase in apoptosis was observed in four cell lines (T-84, HT-29, MCF-7 and DU145) when cells were treated with lycopene. CONCLUSIONS: Our findings show the capacity of lycopene to inhibit cell proliferation, arrest cell cycle in different phases and increase apoptosis, mainly in breast, colon and prostate lines after 96 h. These observations suggest that lycopene may alter cell cycle regulatory proteins depending on the type of cancer and the dose of lycopene administration. Taken together, these data indicated that the antiproliferative effect of lycopene was cellular type, time and dose-dependent. KEY WORDS: lycopene, cancer, bioactive compounds, cell cycle.     

Genetic requirements for cell division in a genomically minimal cell

1. Download : Download high-res image (233KB)
2. Download : Download full-size image

     

Microfluidic cell culture

1. Download : Download high-res image (185KB)
2. Download : Download full-size image

     

Asymmetric cell division safeguards memory CD8 T cell development

1. Download : Download high-res image (134KB)
2. Download : Download full-size image

     

Signal transduction pathways in mast cell granule-mediated endothelial cell activation

BACKGROUND: We have previously shown that incubation of human endothelial cells with mast cell granules results in potentiation of lipopolysaccharide-induced production of interleukin-6 and interleukin-8. AIMS: The objective of the present study was to identify candidate molecules and signal transduction pathways involved in the synergy between mast cell granules and lipopolysaccharide on endothelial cell activation. METHODS: Human umbilical vein endothelial cells were incubated with rat mast cell granules in the presence and absence of lipopolysaccharide, and IL-6 production was quantified. The status of c-Jun amino-terminal kinase and extracellular signal-regulated kinase 1/2 activation, nuclear factor-kappaB translocation and intracellular calcium levels were determined to identify the mechanism of synergy between mast cell granules and lipopolysaccaride. RESULTS: Mast cell granules induced low levels of interleukin-6 production by endothelial cells, and this effect was markedly enhanced by lipopolysaccharide. The results revealed that both serine proteases and histamine present in mast cell granules were involved in this activation process. Mast cell granules increased intracellular calcium, and activated c-Jun amino-terminal kinase and extracellular signal-regulated kinase 1/2. The combination of lipopolysaccharide and mast cell granules prolonged c-Jun amino-terminal kinase activity beyond the duration of induction by either stimulant alone and was entirely due to active proteases. However, both proteases and histamine contributed to calcium mobilization and extracellular signal-regulated kinase 1/2 activation. The nuclear translocation of nuclear factor-kappaB proteins was of greater magnitude in endothelial cells treated with the combination of mast cell granules and lipopolysaccharide. CONCLUSIONS:Mast cell granule serine proteases and histamine can amplify lipopolysaccharide-induced endothelial cell activation, which involves calcium mobilization, mitogen-activated protein kinase activation and nuclear factor-kappaB translocation.     

Space and time in the plant cell wall: relationships between cell type, cell wall rheology and cell function

BACKGROUND: The biomechanical behaviour of plant cells depends upon the material properties of their cell walls and, in many cases, it is necessary that these properties are quite specific. Additionally, physiological regulation may require that target cells responding to hormonal signals or environmental factors are able to modulate these characteristics. ARGUMENT: This paper uses a rheological analysis of creep of elongating sunflower (Helianthus annuus) sunflower hypocotyls to demonstrate that the mechanical behaviour of plant cell walls is complex and involves multiple layered processes that can be distinguished from one another by the time-scale over which they lead to a change in tissue dimensions, their sensitivity to pH and temperature, and their responses to changes in spatial arrangement of the cell wall brought about by treatment with high M(r) PEG. Furthermore, it appears possible to regulate individual rheological processes, with limited effect on others, in order to modulate growth without affecting tissue structural integrity. It is proposed that control of the water content of the cell wall and therefore the space between cell wall polymers may be one mechanism by which differential regulation of cell wall biomechanical properties is achieved. This hypothesis is supported by evidence showing that enzyme extracts from growing tissues can cause swelling in cell wall fragments in suspension. IMPLICATIONS: The physiological implications of this complexity are then considered for growing tissues, stomatal guard cells and abscission cells. It is noted that, in each circumstance, a different combination of mechanical properties is required and that differential regulation of properties affecting behaviour over different time-scales is often necessary.     

The ciliary GTPase Arl13b regulates cell migration and cell cycle progression

The GTPase ARL13B is localized to primary cilia; small cellular protrusions that act as antennae. Its defective ARL13B hennin (HNN) variant is linked causally with Joubert Syndrome, a developmental ciliopathy attributed to poor sensing of extracellular chemical gradients. We tested the hypothesis that impaired detection of extracellular voltage gradients also contributes to the HNN phenotype.

In vitro, extracellular electric fields stimulated migration of wild type (WT) and HNN fibroblasts toward the cathode but the field only increased the migration speed of WT cells. Cilia on WT cells did not align to the field vector. HNN cells divided more slowly than WT cells, arresting at the G2/M phase. Mechanistically, HNN cells had reduced phospho-ERK1/2 signaling and elevated levels of Suppressor of Fused protein. These suggest that cells may not be able to read extracellular chemical cues appropriately, resulting in deficits in cell migration and proliferation. Finally, an increase in tubulin stabilization (more detyrosinated tubulin) confirmed the general stagnation of HNN cells, which may further contribute to slower migration and cell cycle progression.

We conclude that Arl13b dysfunction resulted in HNN cell stagnation due to poor growth factor signaling and impaired detection of extracellular electrical gradients, and that the role of Arl13b in cell proliferation may be understated.     

A role of miR-33 for cell cycle progression and cell proliferation

Comment on: Cirera-Salinas D, et al. Cell Cycle 2012; 11:922–33     

Preformed cell structure and cell heredity

This review will first recall the phenomena of “cortical inheritance” observed and genetically demonstrated in Paramecium 40 years ago, and later in other ciliates (Tetrahymena, Oxytricha, Paraurostyla), and will analyze the deduced concept of “cytotaxis” or “structural memory.” The significance of these phenomena, all related (but not strictly restricted) to the properties of ciliary basal bodies and their mode of duplication, will be interpreted in the light of present knowledge on the mechanism and control of basal body/centriole duplication. Then other phenomena described in a variety of organisms will be analyzed or mentioned which show the relevance of the concept of cytotaxis to other cellular processes, mainly (1) cytoskeleton assembly and organization with examples on ciliates, trypanosome, mammalian cells and plants, and (2) transmission of polarities with examples on yeast, trypanosome and metazoa. Finally, I will discuss some aspects of this particular type of non-DNA inheritance: (1) why so few documented examples if structural memory is a basic parameter in cell heredity, and (2) how are these phenomena (which all rely on protein/protein interactions, and imply a formatting role of preexisting proteinic complexes on neo-formed proteins and their assembly) related to prions?Key words: Paramecium, basal-body, centriole, basal-body duplication, cell polarity, structural inheritance, cytotaxis, cell memory, epigenetics     

Yeast toxicogenomics: lessons from a eukaryotic cell model and cell factory

1. Download : Download high-res image (249KB)
2. Download : Download full-size image

     

Ovarian theca cell

Theca cells are the endocrine cells associated with ovarian follicles that play an essential role in fertility by producing the androgen substrate required for ovarian estrogen biosynthesis. Theca cells differentiate from the interfollicular stroma in response to proteins secreted from growing follicles. The most common endocrine cause of infertility is associated with excessive proliferation of theca cells and ovarian hyperandrogenism. Cell facts: -ovarian androgen-producing cells; -are associated only with developing follicles; -over-activity of theca cells causes infertility due to hyperandrogenism; -under-activity of theca cells causes infertility due to lack of estrogen. Theca cells: androgen-producing cells in the ovary.     

Neoantigen-driven B cell and CD4 T follicular helper cell collaboration promotes anti-tumor CD8 T cell responses

1. Download : Download high-res image (168KB)
2. Download : Download full-size image

     

Raman activated cell sorting

1. Download : Download high-res image (174KB)
2. Download : Download full-size image

     

Human and mouse trigeminal ganglia cell atlas implicates multiple cell types in migraine

1. Download : Download high-res image (151KB)
2. Download : Download full-size image

     

Some theoretical and practical considerations for multivariate statistical cell classification useful in autologous stem cell transplantation and tumor cell purging.

BACKGROUND: As flow cytometric data becomes more complex, it becomes increasingly difficult to classify cells using conventional flow cytometry data techniques based on visual classification of the data by user-drawn regions. This paper shows some simple applications of multivariate statistical classification to classify flow cytometric data. METHODS: Discriminant Function Analysis (DFA) and Logistic Regression (LR) analysis techniques were evaluated with respect to their potential utility in the problem of detecting human breast cancer cells within normal bone marrow cells. Data sets having defined properties were employed to evaluate the potential utility of these statistical classification techniques whose performance was measured by ROC analysis. RESULTS: Two extreme but reasonable situations are presented: (1) data where the separation of cells was obvious by visual inspection and (2) data where major overlaps in the values of the individual FCM parameters made intuitive classification improbable. Both DFA and LR analysis were able to classify the cells of each type with acceptable accuracy and yield.CONCLUSIONS: The excellent empirical performance of both DFA and LR techniques, suggests that they offer promising approaches for classifying multiparameter FCM data using objective rules that may represent an improvement over commonly employed ad hoc approaches.