共查询到20条相似文献,搜索用时 0 毫秒
1.
A cell mechanical stimulation equipment, based on cell substrate deformation, and a more sensitive method for measuring adhesion of cells were developed. A probe, precisely positioned close to the cell, was capable of a vertical localized mechanical stimulation with a temporal frequency of 207 Hz, and strain magnitude of 50%. This setup was characterized and used to probe the response of Human Umbilical Endothelial Vein Cells (HUVECs) in terms of calcium signaling. The intracellular calcium ion concentration was measured by the genetically encoded Cameleon biosensor, with the Transient Receptor Potential cation channel, subfamily M, member 7 (TRPM7) expression inhibited. As TRPM7 expression also regulates adhesion, a relatively simple method for measuring adhesion of cells was also developed, tested and used to study the effect of adhesion alone. Three adhesion conditions of HUVECs on polyacrylamide gel dishes were compared. In the first condition, the substrate is fully treated with Sulfo-SANPAH crosslinking and fibronectin. The other two conditions had increasingly reduced adhesion: partially treated (only coated with fibronectin, with no use of Sulfo-SANPAH, at 5% of the normal amount) and non-treated polyacrylamide gels. The cells showed adhesion and calcium response to the mechanical stimulation correlated to the degree of gel treatment: highest for fully treated gels and lowest for non-treated ones. TRPM7 inhibition by siRNA on HUVECs caused an increase in adhesion relative to control (no siRNA treatment) and non-targeting siRNA, but a decrease to 80% of calcium response relative to non-targeting siRNA which confirms the important role of TRPM7 in mechanotransduction despite the increase in adhesion. 相似文献
2.
Prohibitin 1 (PHB1) is a highly conserved protein that together with its homologue prohibitin 2 (PHB2) mainly localizes to the inner mitochondrial membrane. Although it was originally identified by its ability to inhibit G1/S progression in human fibroblasts, its role as tumor suppressor is debated. To determine the function of prohibitins in maintaining cell homeostasis, we generated cancer cell lines expressing prohibitin-directed shRNAs. We show that prohibitin proteins are necessary for the proliferation of cancer cells. Down-regulation of prohibitin expression drastically reduced the rate of cell division. Furthermore, mitochondrial morphology was not affected, but loss of prohibitins did lead to the degradation of the fusion protein OPA1 and, in certain cancer cell lines, to a reduced capability to exhibit anchorage-independent growth. These cancer cells also exhibited reduced adhesion to the extracellular matrix. Taken together, these observations suggest prohibitins play a crucial role in adhesion processes in the cell and thereby sustaining cancer cell propagation and survival. 相似文献
3.
The cytoskeletal protein vinculin is a major regulator of cell adhesion and attaches to the cell surface by binding to specific phospholipids. Structural, biochemical, and biological studies provided much insight into how vinculin binds to membranes, what components it recognizes, and how lipid binding is regulated. Here we discuss the roles and mechanisms of phospholipids in regulating the structure and function of vinculin and of its muscle-specific metavinculin splice variant. A full appreciation of these processes is necessary for understanding how vinculin regulates cell motility, migration, and wound healing, and for understanding of its role in cancer and cardiovascular diseases. 相似文献
4.
5.
6.
Robust tissue patterning is crucial to many processes during development. The "French Flag" model of patterning, whereby naïve cells in a gradient of diffusible morphogen signal adopt different fates due to exposure to different amounts of morphogen concentration, has been the most widely proposed model for tissue patterning. However, recently, using time-lapse experiments, cell sorting has been found to be an alternative model for tissue patterning in the zebrafish neural tube. But it remains unclear what the sorting mechanism is. In this article, we used computational modeling to show that two mechanisms, chemotaxis and differential adhesion, are needed for robust cell sorting. We assessed the performance of each of the two mechanisms by quantifying the fraction of correct sorting, the fraction of stable clusters formed after correct sorting, the time needed to achieve correct sorting, and the size variations of the cells having different fates. We found that chemotaxis and differential adhesion confer different advantages to the sorting process. Chemotaxis leads to high fraction of correct sorting as individual cells will either migrate towards or away from the source depending on its cell type. However after the cells have sorted correctly, there is no interaction among cells of the same type to stabilize the sorted boundaries, leading to cell clusters that are unstable. On the other hand, differential adhesion results in low fraction of correct clusters that are more stable. In the absence of morphogen gradient noise, a combination of both chemotaxis and differential adhesion yields cell sorting that is both accurate and robust. However, in the presence of gradient noise, the simple combination of chemotaxis and differential adhesion is insufficient for cell sorting; instead, chemotaxis coupled with delayed differential adhesion is required to yield optimal sorting. 相似文献
7.
8.
Jasmina Makarevi? Jochen Rutz Eva Juengel Silke Kaulfuss Igor Tsaur Karen Nelson Jesco Pfitzenmaier Axel Haferkamp Roman A. Blaheta 《PloS one》2014,9(10)
The cyanogenic diglucoside amygdalin, derived from Rosaceae kernels, is employed by many patients as an alternative anti-cancer treatment. However, whether amygdalin indeed acts as an anti-tumor agent is not clear. Metastasis blocking properties of amygdalin on bladder cancer cell lines was, therefore, investigated. Amygdalin (10 mg/ml) was applied to UMUC-3, TCCSUP or RT112 bladder cancer cells for 24 h or for 2 weeks. Tumor cell adhesion to vascular endothelium or to immobilized collagen as well as tumor cell migration was examined. Effects of drug treatment on integrin α and β subtypes, on integrin-linked kinase (ILK) and total and activated focal adhesion kinase (FAK) were also determined. Integrin knock-down was carried out to evaluate integrin influence on migration and adhesion. A 24 h or 2 week amygdalin application distinctly reduced tumor cell adhesion and migration of UMUC-3 and RT112 cells. TCCSUP adhesion was also reduced, but migration was elevated under amygdalin. Integrin subtype expression was significantly and specifically altered by amygdalin depending on the cell line. ILK was moderately, and activated FAK strongly, lost in all tumor cell lines in the presence of amygdalin. Knock down of β1 integrin caused a significant decrease in both adhesion and migration of UMUC-3 cells, but a significant increase in TCCSUP adhesion. Knock down of β4 integrin caused a significant decrease in migration of RT112 cells. Since the different actions of amygdalin on the different cell lines was mirrored by β1 or β4 knock down, it is postulated that amygdalin influences adhesion and migratory properties of bladder cancer cells by modulating β1 or β4 integrin expression. The amygdalin induced increase in TCCSUP migratory behavior indicates that any anti-tumor benefits from amygdalin (seen with the other two cell lines) may depend upon the cancer cell type. 相似文献
9.
During embryogenesis, LHRH neurons arise in the olfactory epithelium, migrate along the olfactory nerve, and enter the forebrain. We have examined the distribution of several cell adhesion molecules (CAMs) in the developing chick olfactory system and brain to determine whether differential distributions of these adhesion molecules might be important in pathway choices made by migrating LHRH neurons. Single- and double-label immunocytochemical studies indicated that high levels of N-CAM and N-cadherin were expressed throughout the olfactory epithelium and not restricted to the medial half of the olfactory epithelium where most of the LHRH neurons originate. Further, high levels of N-CAM, Ng-CAM, and N-cadherin were uniformly expressed throughout the entire olfactory nerve while migrating LHRH neurons were confined to the medial half of the nerve. However, once LHRH neurons reach the brain, they migrate dorsally and caudally, tangential to the medial surface of the forebrain, along a region enriched in N-CAM and Ng-CAM. After this first stage of migration within the brain, LHRH neurons migrate laterally. At this stage, there is no correlation between the intensity of N-CAM and Ng-CAM immunostaining and the location of LHRH neurons. These results suggest that N-CAM, Ng-CAM, and N-cadherin do not play a guiding role in LHRH neuronal migration through the olfactory epithelium and olfactory nerve but that migrating LHRH neurons may follow a "CAM-trail" of N-CAM and Ng-CAM along the medial surface of the forebrain. 相似文献
10.
Biochemical Characterization of Different Molecular Forms of the Neural Cell Adhesion Molecule L1 总被引:10,自引:2,他引:10
Karin Sadoul Rémy Sadoul reas Faissner Melitta Schachner 《Journal of neurochemistry》1988,50(2):510-521
The neural cell adhesion molecule L1 is a phosphorylated, integral membrane glycoprotein that is recovered from adult mouse brain tissue by immunoaffinity chromatography as a set of polypeptides with apparent molecular masses of 200, 180, 140, and 80 kilodaltons (L1–200, L1–180, L1–140, and L1–80, respectively). It has been shown that L1–140 and the phosphorylated L1–80 is generated from L1–200 by mild proteolytic treatment of intact cells. In the present study we have investigated the structural relationships between the different molecular forms of L1 and their location with regard to the surface membrane. We could show that L1–200 has two preferred cleavage sites, one that generates the amino terminal, extracellularly exposed L1–140 and the carboxy terminal L1–80 that spans the membrane. Cleavage at the other site leads to the generation of the amino terminally located L1–180 and the membrane-attached, phosphorylated carboxy terminal L1–30. This site is cleaved during treatment of live cultured cells with broad-spectrum, protease-free phospholipase C (but not phosphatidylinositol-specific phospholipase C) or exposure to sodium azide or cyanogen bromide. Other conditions that cause damage to cells do not lead to the generation of L1–180 and L1–30, suggesting a particular cell-intrinsic cleavage mechanism. L1–180 is truly soluble in aqueous solutions, since it can be recovered from culture supernatants and in the supernatant of a crude membrane fraction after incubation for 2 h at 37°C. Although trypsin treatment alone does not release L1–140 into the supernatant, combination of phospholipase C and mild tryptic treatment leads to the release of L1–140 and L1–50, the latter being most likely the extracellularly exposed domain of L1–80 that is complementary to the membrane-integrated phosphorylated L1–30. Phase separation experiments with Triton X-114 show that the released forms of L1–180 and L1–140 distribute into the aqueous phase, whereas they distribute into the detergent phase when in association with L1–200 or L1–80. However, when L1–80 is cleaved to yield the soluble L1–50 and membrane-anchored L1–30, L1–140 is released into the supernatant together with L1–50. A strong affinity of L1–200, L1–140, and L1–80 to each other is also indicated by the fact that they incorporate together into liposomes and separate only under strong detergent conditions. Also, a strong tendency to aggregate is observed for L1-containing liposomes, but not for those containing the adhesion molecules neural cell adhesion molecule and myelin-associated glycoprotein. Although the physiological roles of the soluble L1 forms, their mode of generation, and the strong affinity for each other remain to be investigated, the availability of soluble forms of L1 opens the possibility to use them as probes for the functional properties of L1 in assay systems involving live cells in vitro. 相似文献
11.
Hendra Setiadi Gerald Sedgewick Stanley L. Erlandsen Rodger P. McEver 《The Journal of cell biology》1998,142(3):859-871
Flowing leukocytes tether to and roll on P-selectin, a receptor on endothelial cells that is rapidly internalized in clathrin-coated pits. We asked whether the association of P-selectin with clathrin-coated pits contributes to its adhesive function. Under flow, rolling neutrophils accumulated efficiently on CHO cells expressing wild-type P-selectin or a P-selectin construct with a substitution in the cytoplasmic domain that caused even faster internalization than that of the wild-type protein. By contrast, far fewer rolling neutrophils accumulated on CHO cells expressing P-selectin constructs with a deletion or a substitution in the cytoplasmic domain that impaired internalization. Neutrophils rolled on the internalization-competent constructs with greater adhesive strength, slower velocity, and more uniform motion. Flowing neutrophils tethered equivalently to internalization-competent or internalization-defective P-selectin, but after tethering, they rolled further on internalization-competent P-selectin. Confocal microscopy demonstrated colocalization of α-adaptin, a component of clathrin-coated pits, with wild-type P-selectin, but not with P-selectin lacking the cytoplasmic domain. Treatment of CHO cells or endothelial cells with hypertonic medium reversibly impaired the clathrin-mediated internalization of P-selectin and its ability to support neutrophil rolling. Interactions of the cytoplasmic domain of P-selectin with clathrin-coated pits provide a novel mechanism to enhance leukocyte adhesion under flow. 相似文献
12.
Loredana Mauro Diego Sisci Monica Bartucci Michele Salerno Jerry Kim Timothy Tam Marina A. Guvakova Sebastiano Ando Eva Surmacz 《Experimental cell research》1999,252(2):439
The oncogenic SHC proteins are signaling substrates for most receptor and cytoplasmic tyrosine kinases (TKs) and have been implicated in cellular growth, transformation, and differentiation. In tumor cells overexpressing TKs, the levels of tyrosine phosphorylated SHC are chronically elevated. The significance of amplified SHC signaling in breast tumorigenesis and metastasis remains unknown. Here we demonstrate that seven- to ninefold overexpression of SHC significantly altered interactions of cells with fibronectin (FN). Specifically, in human breast cancer cells overexpressing SHC (MCF-7/SHC) the association of SHC with α5β1 integrin (FN receptor) was increased, spreading on FN was accelerated, and basal growth on FN was reduced. These effects coincided with an early decline of adhesion-dependent MAP kinase activity. Basal motility of MCF-7/SHC cells on FN was inhibited relative to that in several cell lines with normal SHC levels. However, when EGF or IGF-I was used as the chemoattractant, the locomotion of MCF-7/SHC cells was greatly (approx fivefold) stimulated, while it was only minimally altered in the control cells. These data suggest that SHC is a mediator of the dynamic regulation of cell adhesion and motility on FN in breast cancer cells. 相似文献
13.
Biochemical Specialization of Photosynthetic Cell Layers and Carbon Flow Paths in Suaeda monoica
下载免费PDF全文

Suaeda monoica Frossk. ex J. F. Gmel is a C4 plant with three different photosynthesizing cell layers. The outer chlorenchymatous layer shows a high activity of phosphoenolpyruvate (PEP) carboxylase but none of ribulose bisphosphate (RuBP) carboxylase. The electrophoretic protein band of RuBP carboxylase was missing in this layer. The second chlorenchymatous cells layer shows a very high activity of RuBP carboxylase and NAD malic enzyme and only traces of activity of PEP carboxylase. The third photosynthesizing cell type is comprised of the water tissue. It has moderate activities of RuBP carboxylase and PEP carboxylase. A model for carbon flow in Suaeda monoica leaves is proposed. 相似文献
14.
《Cell cycle (Georgetown, Tex.)》2013,12(11):1478-1481
Fas-associated death domain (FADD)/Mort1 was initially reported as a pro-apoptotic adaptor molecule that recruits the initiator caspases 8 and 10 to promote formation of the death-inducing signal complex (DISC) and mediates receptor induced apoptosis. Recent studies have brought to light ancillary death receptor induced apoptosis-independent activities of FADD that include cell cycle regulation, NF-κB activation, cell proliferation and role during embryonic development. We have recently shown that in lung adenocarcinomas increased FADD mRNA and protein are significantly associated with poor survival and that FADD overexpression was not due to gene amplification and/or mutation. In this study we showed that the nuclear localization of FADD and elevated expression of the phosphorylated form of FADD (p-FADD) correlated most closely with an increase in NF-κB activity and poor clinical outcome. These results suggest that levels of p-FADD may be used as a prognostic biomarker for predicting survival of lung cancer patients. 相似文献
15.
The aims of this study were to examine long-term growth interactions of five probiotic strains (Lactobacillus casei 01, Lactobacillus plantarum HA8, Lactobacillus rhamnosus GG, Lactobacillus reuteri ATCC 55730 and Bifidobacterium lactis Bb12) either alone or in combination with Propionibacterium jensenii 702 in a co-culture system and to determine their adhesion ability to human colon adenocarcinoma cell line Caco-2. Growth
patterns of probiotic Lactobacillus strains were not considerably affected by the presence of P. jensenii 702, whereas lactobacilli exerted a strong antagonistic action against P. jensenii 702. In the co-culture of Bif. lactis Bb12 and P. jensenii 702, a significant synergistic influence on growth of both bacteria was observed (P < 0.05). The results of adhesion assay showed that when probiotic strains were tested in combination, there was evidence
of an associated effect on percentage adherence. However, in most cases these differences were not statistically significant
(P < 0.05). Adhesion percentage of Lb. casei 01 and Lb. rhamnosus GG both decreased significantly in the presence of P. jensenii 702 compared to their adhesion levels when alone (P < 0.05). These results show that the survival and percentage adhesion of some probiotic strains may be influenced by the
presence of other strains and this should be considered when formulating in the probiotic products. 相似文献
16.
Cancer stem cells (CSCs) possess capacity to both self-renew and generate all cells within a tumor, and are thought to drive tumor recurrence. Targeting the stem cell niche to eradicate CSCs represents an important area of therapeutic development. The complex nature of many interacting elements of the stem cell niche, including both intracellular signals and microenvironmental growth factors and cytokines, creates a challenge in choosing which elements to target, alone or in combination. Stochastic stimulation techniques allow for the careful study of complex systems in biology and medicine and are ideal for the investigation of strategies aimed at CSC eradication. We present a mathematical model of the breast cancer stem cell (BCSC) niche to predict population dynamics during carcinogenesis and in response to treatment. Using data from cell line and mouse xenograft experiments, we estimate rates of interconversion between mesenchymal and epithelial states in BCSCs and find that EMT/MET transitions occur frequently. We examine bulk tumor growth dynamics in response to alterations in the rate of symmetric self-renewal of BCSCs and find that small changes in BCSC behavior can give rise to the Gompertzian growth pattern observed in breast tumors. Finally, we examine stochastic reaction kinetic simulations in which elements of the breast cancer stem cell niche are inhibited individually and in combination. We find that slowing self-renewal and disrupting the positive feedback loop between IL-6, Stat3 activation, and NF-κB signaling by simultaneous inhibition of IL-6 and HER2 is the most effective combination to eliminate both mesenchymal and epithelial populations of BCSCs. Predictions from our model and simulations show excellent agreement with experimental data showing the efficacy of combined HER2 and Il-6 blockade in reducing BCSC populations. Our findings will be directly examined in a planned clinical trial of combined HER2 and IL-6 targeted therapy in HER2-positive breast cancer. 相似文献
17.
Differential cell adhesive properties are known to regulate important developmental events like cell sorting and cell migration. Cadherins and protocadherins are known to mediate these cellular properties. Though a large number of such molecules have been predicted, their characterization in terms of interactive properties and cellular roles is far from being comprehensive. To narrow down the tissue context and collect correlative evidence for tissue specific roles of these molecules, we have carried out whole-mount in situ hybridization based RNA expression study for seven cadherins and four protocadherins. In developing chicken embryos (HH stages 18, 22, 26 and 28) cadherins and protocadherins are expressed in tissue restricted manner. This expression study elucidates precise expression domains of cell adhesion molecules in the context of developing embryos. These expression domains provide spatio-temporal context in which the function of these genes can be further explored. 相似文献
18.
Marco Tarantola Albert Bae Danny Fuller Eberhard Bodenschatz Wouter-Jan Rappel William F. Loomis 《PloS one》2014,9(9)
Vegetative and developed amoebae of Dictyostelium discoideum gain traction and move rapidly on a wide range of substrata without forming focal adhesions. We used two independent assays to quantify cell-substrate adhesion in mutants and in wild-type cells as a function of development. Using a microfluidic device that generates a range of hydrodynamic shear stress, we found that substratum adhesion decreases at least 10 fold during the first 6 hr of development of wild type cells. This result was confirmed using a single-cell assay in which cells were attached to the cantilever of an atomic force probe and allowed to adhere to untreated glass surfaces before being retracted. Both of these assays showed that the decrease in substratum adhesion was dependent on the cAMP receptor CAR1 which triggers development. Vegetative cells missing talin as the result of a mutation in talA exhibited slightly reduced adhesive properties compared to vegetative wild-type cells. In sharp contrast to wild-type cells, however, these talA mutant cells did not show further reduction of adhesion during development such that after 5 hr of development they were significantly more adhesive than developed wild type cells. In addition, both assays showed that substrate adhesion was reduced in 0 hr cells when the actin cytoskeleton was disrupted by latrunculin. Consistent with previous observations, substrate adhesion was also reduced in 0 hr cells lacking the membrane proteins SadA or SibA as the result of mutations in sadA or sibA. However, there was no difference in the adhesion properties between wild type AX3 cells and these mutant cells after 6 hr of development, suggesting that neither SibA nor SadA play an essential role in substratum adhesion during aggregation. Our results provide a quantitative framework for further studies of cell substratum adhesion in Dictyostelium. 相似文献
19.
Epithelial ovarian cancers (EOCs) are the leading cause of death from gynecological malignancy in Western societies. Despite advances in surgical treatments and improved platinum-based chemotherapies, there has been little improvement in EOC survival rates for more than four decades 1,2. Whilst stage I tumors have 5-year survival rates >85%, survival rates for stage III/IV disease are <40%. Thus, the high rates of mortality for EOC could be significantly decreased if tumors were detected at earlier, more treatable, stages 3-5. At present, the molecular genetic and biological basis of early stage disease development is poorly understood. More specifically, little is known about the role of the microenvironment during tumor initiation; but known risk factors for EOCs (e.g. age and parity) suggest that the microenvironment plays a key role in the early genesis of EOCs. We therefore developed three-dimensional heterotypic models of both the normal ovary and of early stage ovarian cancers. For the normal ovary, we co-cultured normal ovarian surface epithelial (IOSE) and normal stromal fibroblast (INOF) cells, immortalized by retrovrial transduction of the catalytic subunit of human telomerase holoenzyme (hTERT) to extend the lifespan of these cells in culture. To model the earliest stages of ovarian epithelial cell transformation, overexpression of the CMYC oncogene in IOSE cells, again co-cultured with INOF cells. These heterotypic models were used to investigate the effects of aging and senescence on the transformation and invasion of epithelial cells. Here we describe the methodological steps in development of these three-dimensional model; these methodologies aren''t specific to the development of normal ovary and ovarian cancer tissues, and could be used to study other tissue types where stromal and epithelial cell interactions are a fundamental aspect of the tissue maintenance and disease development. 相似文献
20.
Olimpia Gamucci Alice Bertero Maria Ada Malvindi Stefania Sabella Pier Paolo Pompa Barbara Mazzolai Giuseppe Bardi 《Journal of visualized experiments : JoVE》2014,(85)
Engineered nanoparticles are endowed with very promising properties for therapeutic and diagnostic purposes. This work describes a fast and reliable method of analysis by flow cytometry to study nanoparticle interaction with immune cells. Primary immune cells can be easily purified from human or mouse tissues by antibody-mediated magnetic isolation. In the first instance, the different cell populations running in a flow cytometer can be distinguished by the forward-scattered light (FSC), which is proportional to cell size, and the side-scattered light (SSC), related to cell internal complexity. Furthermore, fluorescently labeled antibodies against specific cell surface receptors permit the identification of several subpopulations within the same sample. Often, all these features vary when cells are boosted by external stimuli that change their physiological and morphological state. Here, 50 nm FITC-SiO2 nanoparticles are used as a model to identify the internalization of nanostructured materials in human blood immune cells. The cell fluorescence and side-scattered light increase after incubation with nanoparticles allowed us to define time and concentration dependence of nanoparticle-cell interaction. Moreover, such protocol can be extended to investigate Rhodamine-SiO2 nanoparticle interaction with primary microglia, the central nervous system resident immune cells, isolated from mutant mice that specifically express the Green Fluorescent Protein (GFP) in the monocyte/macrophage lineage. Finally, flow cytometry data related to nanoparticle internalization into the cells have been confirmed by confocal microscopy. 相似文献