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1.
Arjan W. Griffioen Eveliene Horst Karl Heinz Heider Vera J. M. Wielenga GÜ Unther R. Adolf Peter Herrlich Steven T. Pals 《Cell communication & adhesion》1994,2(3):195-200
Recently, splice variants of CD44 have been described that confer metastatic potential to non-metastasizing rat pancreatic carcinoma and sarcoma cell lines. Using antibodies against variant CD44 (CD44v) sequences, we have examined the expression of variant CD44 glycoproteins on human lymphoid cells and tissues and in colorectal neoplasia. Lymphohematopoietic cells express low levels of CD44v glycoproteins. During the process of lymphocyte activation in vitro and in vivo, expression of CD44v glycoproteins is transiently upregulated. The reaction pattern of various antibodies indicates that these CD44 variants contain the domain encoded by exon v6, which is part of the variant that confers metastatic capability. In human colorectal neoplasia we observed overexpression of CD44 splice variants in all invasive carcinomas. Already at early stages of colorectal tumor progression exon v5 epitopes were overexpressed. Tumor progression was strongly related to expression of CD44 isoforms containing exon v6 encoded domains. The findings establish CD44 variants as tumor progression markers in colorectal cancer. 相似文献
2.
《Cell communication & adhesion》2013,20(3):195-200
Recently, splice variants of CD44 have been described that confer metastatic potential to non-metastasizing rat pancreatic carcinoma and sarcoma cell lines. Using antibodies against variant CD44 (CD44v) sequences, we have examined the expression of variant CD44 glycoproteins on human lymphoid cells and tissues and in colorectal neoplasia. Lymphohematopoietic cells express low levels of CD44v glycoproteins. During the process of lymphocyte activation in vitro and in vivo, expression of CD44v glycoproteins is transiently upregulated. The reaction pattern of various antibodies indicates that these CD44 variants contain the domain encoded by exon v6, which is part of the variant that confers metastatic capability. In human colorectal neoplasia we observed overexpression of CD44 splice variants in all invasive carcinomas. Already at early stages of colorectal tumor progression exon v5 epitopes were overexpressed. Tumor progression was strongly related to expression of CD44 isoforms containing exon v6 encoded domains. The findings establish CD44 variants as tumor progression markers in colorectal cancer. 相似文献
3.
Jayne Lesley Robert Hyman Nicole English Jonathan B Catterall Graham A Turner 《Glycoconjugate journal》1997,14(5):611-622
CD44 is a major cell surface receptor for the glycosaminoglycan, hyaluronan (HA). CD44 binds HA specifically, although certain
chondroitin-sulfate containing proteoglycans may also be recognized. CD44 binding of HA is regulated by the cells in which
it is expressed. Thus, CD44 expression alone does not correlate with HA binding activity. CD44 is subject to a wide array
of post-translational carbohydrate modifications, including N-linked, O-linked and glycosaminoglycan side chain additions.
These modifications, which differ in different cell types and cell activation states, can have profound effects on HA binding
function and are the main mechanism of regulating CD44 function that has been described to date. Some glycosaminoglycan modifications
also affect ligand binding specificity, allowing CD44 to interact with proteins of the extracellular matrix, such as fibronectin
and collagen, and to sequester heparin binding growth factors. It is not yet established whether the HA binding function of
CD44 is responsible for its proposed involvement in inflammation. It has been shown, however, that CD44/HA interactions can
mediate leukocyte rolling on endothelial and tissue substrates and that CD44-mediated recognition of HA can contribute to
leukocyte activation. Changes in CD44 expression (mainly up-regulation, occasionally down-regulation, and frequently alteration
in the pattern of isoforms expressed) are associated with a wide variety of cancers and the degree to which they spread; however,
in other cancers, the CD44 pattern remains unchanged. Increased expression of CD44 is associated with increased binding to
HA and increased metastatic potential in some experimental tumor systems; however, in other systems increased HA binding and
metastatic potential are not correlated. CD44 may contribute to malignancy through changes in the regulation of HA recognition,
the recognition of new ligands and/or other new biological functions of CD44 that remain to be discovered. Abbreviations:
aa, amino acid(s); CS, chondroitin sulfate; CSPG, chondroitin sulfate containing proteoglycan; CD44H, ‘hematopoietic’, also
called ‘standard’, isoform of CD44 which contains none of the alternatively spliced variant exons; CD44-Rg, CD44 receptor
globulin, a secreted chimaeric protein composed of the external domain of the adhesion receptor CD44 and the hinge, CH2 and
CH3 regions of human immunoglobulin-G heavy chain; ECM, extracellular matrix; GAG, glycosaminoglycan; HA, hyaluronan; HS,
heparan sulfate; KS, keratan sulfate; PB, peripheral blood; PBL, peripheral blood lymphocytes
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
4.
Highly malignant neuroblastoma tumors with MYCN amplification have been shown to downregulate the expression of the CD44 adhesion receptor. We have previously shown that MYCN amplified neuroblastoma cell lines either lack CD44 expression or express a nonfunctional, nonhyaluronic acid-binding CD44 receptor. By analysis of cells with manipulated expression of either CD44 or MYCN, we demonstrate that transfection of cells with a CD44 full-length cDNA construct produced a functional receptor in single copy MYCN cells and a nonfunctional CD44 receptor in MYCN amplified cells, similar to the CD44 receptor expressed by cells with enforced MYCN. Analysis of the in vivo growth properties of the transfectants revealed that the restoration of a functional CD44 receptor in nonamplified cells resulted in the suppression of in vivo cell growth, therefore linking the MYCN-related lack of hyaluronic acid-binding function of CD44 to the highly tumorigenic properties of a subset of neuroblastoma cells. 相似文献
5.
Although it is now clear that several subpopulations of neural stem cells (NSCs) exist during early development and adulthood, the angiogenic potential of NSCs remains a subject of debate. Here, we report that CD44(+) CD90(+) cells isolated from primary neurospheres can form vascular-tube structures in vitro. NSCs isolated from the mouse embryonic cortex formed neurospheres when cultured in serum-free medium containing 20ng/ml basic fibroblast growth factor (bFGF). CD44(+) CD90(+) cells were enriched from the neurospheres using an EPICS ALTRA flow cytometer, and antibodies against CD44 and CD90. The purified CD44(+) CD90(+) cells generated neurospheres, and differentiated into neurons and astrocytes. When the cells were inoculated into collagen gels and cultured with 20% fetal bovine serum plus bFGF for 7 days, vascular tube-like structures were formed. These results indicate that CD44(+) CD90(+) cells have the ability to generate neurospheres and to form vascular tubes. 相似文献
6.
黏附分子CD24在肿瘤转移中作用 总被引:6,自引:0,他引:6
CD24属糖基磷脂酰肌醇锚蛋白。作为P-选择素配体的黏附分子,其可调节B细胞发育和神经发生。研究显示,CD24高表达在多种肿瘤细胞表面,参与肿瘤的发生发展。已通过体外试验和动物模型证实CD24对多种肿瘤生长和转移相关的肿瘤细胞特性具有调节作用;结合人肿瘤组织研究显示,CD24和乳腺癌、前列腺癌、胰腺癌及肝内胆管癌等肿瘤患者的生存率及预后密切相关。因此,以CD24为靶向的肿瘤诊断和治疗有着诱人的临床应用前景。 相似文献
7.
Nicola Nylander Lynne T. Smith Robert A. Underwood Michael Piepkorn 《In vitro cellular & developmental biology. Animal》1998,34(2):182-188
Summary Much of the autonomous growth of cultured keratinocytes is attributable to the signaling of amphiregulin, a heparin-binding
autocrine growth factor, through the epidermal growth factor receptor. Emerging evidence suggests, moreover, that the membrane
proteoglycan, CD44, is a cofactor for the interaction of heparin-binding ligands with their receptors. This model was evaluated
by characterizing the patterns of the immunolabeled molecules in cultured human neonatal keratinocytes, to test the hypothesis
that involvement in a common function results in coordinate segregation within or on the cell. The molecules were localized
by double immunofluorescence labeling to detect amphiregulin and either the epidermal growth factor receptor or CD44, and
the immunostained products were imaged by scanning laser confocal microscopy. Both amphiregulin and the epidermal growth factor
receptor segregated to a perinuclear distribution and to intercellular contacts. In addition, amphiregulin localized to the
outer leading edge of colonies and focally to intranuclear sites. Metabolic blockade of proteoglycan sulfation with sodium
chlorate inhibited growth of the cells and concurrently enhanced the nuclear, but decreased the outer leading edge, labeling
for amphiregulin. There was no nuclear or perimeter labeling for the epidermal growth factor receptor. Cultures co-immunolabeled
for CD44 and amphiregulin exhibited variable perinuclear staining for both, but otherwise CD44 was distributed to intercellular
contacts. The intercellular localizations of CD44 with amphiregulin and of amphiregulin with the epidermal growth factor receptor
were strongly concordant. These data are consistent with a concerted function at intercellular contacts, where cytokine signaling
is mediated via receptor binding and possibly regulated by the CD44 proteoglycan as cofactor. The intranuclear and perimeter
labeling of amphiregulin, however, suggests that this cytokine has additional functions, both in the nucleus and as a matrix
receptor. 相似文献
8.
Kajita M Itoh Y Chiba T Mori H Okada A Kinoh H Seiki M 《The Journal of cell biology》2001,153(5):893-904
Migratory cells including invasive tumor cells frequently express CD44, a major receptor for hyaluronan and membrane-type 1 matrix metalloproteinase (MT1-MMP) that degrades extracellular matrix at the pericellular region. In this study, we demonstrate that MT1-MMP acts as a processing enzyme for CD44H, releasing it into the medium as a soluble 70-kD fragment. Furthermore, this processing event stimulates cell motility; however, expression of either CD44H or MT1-MMP alone did not stimulate cell motility. Coexpression of MT1-MMP and mutant CD44H lacking the MT1-MMP-processing site did not result in shedding and did not promote cell migration, suggesting that the processing of CD44H by MT1-MMP is critical in the migratory stimulation. Moreover, expression of the mutant CD44H inhibited the cell migration promoted by CD44H and MT1-MMP in a dominant-negative manner. The pancreatic tumor cell line, MIA PaCa-2, was found to shed the 70-kD CD44H fragment in a MT1-MMP-dependent manner. Expression of the mutant CD44H in the cells as well as MMP inhibitor treatment effectively inhibited the migration, suggesting that MIA PaCa-2 cells indeed use the CD44H and MT1-MMP as migratory devices. These findings revealed a novel interaction of the two molecules that have each been implicated in tumor cell migration and invasion. 相似文献
9.
《FEBS letters》2014,588(24):4573-4582
Loss of endothelial adherens junctions is involved in tumor metastasis. Here, we demonstrate that, in the metastatic Lu1205 melanoma cells, expression of the CD44 variant CD44v8-v10 induced junction disassembly and vascular endothelial (VE)-cadherin phosphorylation at Y658 and Y731. Short interfering RNA (siRNA)-mediated CD44 knockdown or sialic acid cleavage reversed these effects. Moreover, microspheres coated with recombinant CD44v8-v10 promoted endothelial junction disruption. Overexpression of CD44v8-v10 but not of standard CD44 (CD44s) promoted gap formation in the non-metastatic WM35 melanoma cells, whereas CD44 knockdown or neuraminidase treatment dramatically diminished melanoma transendothelial migration. Endothelial cells transfected with the phosphomimetic VE-cadherin mutant Y658E supported transmigration of CD44-silenced Lu1205 cells. Our findings imply that CD44 variant isoform (CD44v) but not CD44s regulates endothelial junction loss, promoting melanoma extravasation. 相似文献
10.
目的探讨慢性胃炎胃粘膜肠化生CD44、CD44V6及cyclin D、Cyclin E表达的意义。方法利用免疫细胞化学技术对39例伴有肠化生的慢性胃炎和5例正常人胃窦粘膜的活检组织进行检查。结果正常人胃窦粘膜上皮,腺上皮对CD44、CD44V6、Cyclin D1和Cyclin E均为阴性,但在有神经内分泌样细胞的粘膜,CD44V6和cyclin D1为阳性。慢性胃炎肠化生区和不典型增生区除CD44为阴性外,CD44V6 mcyclin D1和cyclin E均呈现不同的阳性反应,但未见有阳性的神经内分泌样细胞。问质细胞大都呈阳性反应。结论CD44V6、cyclin D1和cyclin E可能是胃癌前状态的早期事件,而CD44可能为胃癌晚期的标志物。 相似文献
11.
目的测定隐球菌性脑膜炎小鼠脑组织中CD44表达,探讨CD44在隐球菌性脑膜炎发病机制中的作用。方法隐球菌性脑膜炎免疫抑制小鼠为实验组,未接种隐球菌的免疫抑制小鼠为对照组,应用免疫组化法检测实验组6h、12h、24h、48h、72h、4d、7d小鼠脑组织CD44表达与对照组的变化。结果对照组小鼠脑组织CD44均匀分布在脑细胞膜上。实验组隐球菌作用小鼠48h、72h后,CD44在小鼠脑组织脑膜侧分布增加,而在脑实质侧CD44的分布明显减少。病灶周围的脑组织CD44分布也一侧增加,另一侧分布减少。结论隐球菌侵入小鼠脑组织后,隐球菌诱导CD44向脑组织的一侧移行,向脑膜方向聚集。病灶周围脑组织CD44分布也不均匀。说明隐球菌性脑膜炎的发生与CD44有密切的关系。 相似文献
12.
《Cell communication & adhesion》2013,20(4):331-347
Migration of some tumor cells, and their lodgment in target organs, is dependent on the activation of cell surface CD44 receptor, usually detected by its ability to bind hyaluronic acid (HA) or other ligands. In an attempt to reveal the mechanism of tumor cell CD44 activation, we compared the physical and chemical properties of CD44 in nonactivated LB cell lymphoma with those in phorbol 12-myristate 13-acetate (PMA)-activated LB cells and of an LB cell subline (designated HA9) expressing constitutively-active CD44. In contrast to nonactivated LB cells, PMA-activated LB cells and HA9 cells displayed a CD44-dependent ability to bind HA. The ability of activated cell CD44 to bind HA was not dependent on microfilament or microtubule integrity or on changes in CD44 mobility on the membrane plane, indicating that the CD44 activation status is not associated with cytoskeleton function. Aside from the increased expression of CD44 on the surface of PMA-activated LB cells and HA9 cells, qualitative differences between the CD44 of nonactivated and activated LB cells were also detected: the CD44 of the activated lymphoma was (i) larger in molecular size, (ii) displayed a broader CD44 isoform repertoire, including a CD44 variant that binds HA, and (iii) its glycoprotein contained less sialic acid. Indeed, after removal of sialic acid from their cell surface by neuraminidase, LB cells acquired the ability to bind HA. However, a reduced dose of neuraminidase did not confer HA binding on LB cells, unless they were also activated by a low concentration of PMA, which by itself was ineffective. Similarly, under suboptimal conditions, a synergistic effect was obtained with tunicamycin and PMA: each one alone was ineffective but in combination they induced the acquisition of HA binding by the lymphoma cells, while their CD44 expression was not enhanced. Unveiling of the activation mechanism of CD44, by exposing the cells to PMA stimulation or to deglycosylation, is not only academically important, but it also has practical implications, as activated CD44 may be involved in the support of tumor progression. 相似文献
13.
The JB6 mouse epidermal cell model system is being used to study the mechanism of promotion of transformation. Promotion of anchorage independence in JB6 cells occurs in response to second-stage but not first-stage promoters, and is inhibited by inhibitors of second-stage not first-stage promotion. A number of variants that are resistant to the phorbol diester TPA have been derived. Some are resistant to plateau density mitogenic stimulation by TPA; others are resistant to promotion of anchorage independence by TPA. Some of the mitogen-resistant variants were promotable by TPA, thus ruling out a requirement for TPA mitogenesis in promotion of transformation in JB6 cells. TPA promotable clones were also sensitive to mezerein and EGF while the TPA nonpromotable variants were also resistant to mezerein and EGF, suggesting that sensitivity to promoters in these JB6 cells is determined at a level distal to receptor binding. Promotion sensitivity did not require available EGF receptors since two TPA promotable variants were EGF receptorless. The mitogenic response of JB6 cells to TPA may however be mediated by EGF since four of four mitogen-resistant variants showed low to zero levels of EGF binding. Tumor promoting phorbol esters produce specific changes in cellular gangliosides. Certain of these changes occur in promotable but not nonpromotable variants of JB6 cells, suggesting that ganglioside changes may be involved in the process of promotion of transformation. 相似文献
14.
15.
CD44 is a widely expressed cell adhesion molecule that binds hyaluronan, an extracellular matrix glycosaminoglycan, in a tightly regulated manner. This regulated interaction has been implicated in inflammation and tumor metastasis. CD44 exists in the standard form, CD44H, or as higher molecular mass isoforms due to alternative splicing. Here, we identify serine 180 in human CD44H as the site of chondroitin sulfate addition and show that lack of chondroitin sulfate addition at this site enhances hyaluronan binding by CD44. A CD44H-immunoglobulin fusion protein expressed in HEK293 cells, and CD44H expressed in murine L fibroblast cells were modified by chondroitin sulfate, as determined by reduced sulfate incorporation after chondroitinase ABC treatment. Mutation of serine 180 or glycine 181 in CD44H reduced chondroitin sulfate addition and increased hyaluronan binding, indicating that serine 180 is the site for chondroitin sulfate addition in CD44H and that this negatively regulates hyaluronan binding. 相似文献
16.
CD147对白血病细胞U937生长和肿瘤形成的影响 总被引:1,自引:0,他引:1
目的:研究CD147对白血病细胞U937生长和肿瘤形成的影响。方法:分别采用脂多糖(LPS)或CD147单克隆抗体处理U937细胞;用RT-PCR和流式细胞术分别在mRNA和蛋白水平检测各组中CD147的表达情况;用流式细胞术检测在LtX3和CD147单克隆抗体作用下U937细胞周期的变化;用MTT法对各组细胞的生长状况进行分析;将细胞经皮下接种于裸鼠体内,对各组间肿瘤生长速度、肿瘤体积及裸鼠存活时间进行统计分析。结果:LPS在体外能够诱导自血病细胞U937表面CD147的表达,同时细胞增殖旺盛,但细胞凋亡数增加;使用CD147抗体阻断CD147后,能够将细胞周期阻断在G0/G1期,细胞活力下降,并诱导细胞凋亡;CD147抗体体外预处理能够抑制U937细胞在裸鼠体内的生长,使小鼠存活时间延长。结论:LPS可诱导U937细胞表面CD147分子表达增加,从而促进U937细胞的生长和肿瘤形成。 相似文献
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18.
Internalization of the Hyaluronan Receptor CD44 by Chondrocytes 总被引:1,自引:0,他引:1
Chondrocytes express CD44 as a primary receptor for the matrix macromolecule hyaluronan. Hyaluronan is responsible for the retention and organization of proteoglycan within cartilage, and hyaluronan-chondrocyte interactions are important for the assembly and maintenance of the cartilage matrix. Bovine articular chondrocytes were used to study the endocytosis and turnover of CD44 and the effects of receptor occupancy on this turnover. Matrix-intact chondrocytes exhibit approximately a 6% internalization of cell surface CD44 by 4 h. Treatment with Streptomyces hyaluronidase to remove endogenous pericellular matrix increased internalization to approximately 20% of cell surface CD44 at 4 h. This turnover could be partially inhibited by the addition of exogenous hyaluronan to these matrix-depleted chondrocytes. Cell surface biotin-labeled CD44 was internalized by chondrocytes and this internalization was decreased in the presence of hyaluronan. Colocalization of internalized CD44 and fluorescein-labeled hyaluronan in intracellular vesicles correlates with the previous results of receptor-mediated endocytosis pathway for the degradation of hyaluronan by acid hydrolases. Taken together, our results indicate that CD44 is internalized by chondrocytes and that CD44 turnover is modulated by occupancy with hyaluronan. 相似文献
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20.
Hyaluronan, a high-molecular-weight glycosaminoglycan of the extracellular matrix, is prominent during rapid tissue growth and repair. It stimulates cell motility and hydrates tissue, providing an environment that facilitates cell movement. Markedly enhanced levels of hyaluronan also occur in the stroma surrounding human cancers, thus providing an environment that promotes spread of cancer cells. The ability of malignant tumors to generate lactate, even in the presence of adequate oxygen, is known as the Warburg effect. Early in wound healing as blood and oxygen supply decrease, lactate levels increase, as does stromal hyaluronan, suggesting a cause-and-effect relationship. Similarly, peritumor stromal fibroblast hyaluronan may be a response to cancer cell lactate. To test this, fibroblasts were cultured in the presence of lactate. With increasing lactate, higher levels of hyaluronan were observed, as were levels of CD44 expression, the predominant receptor for hyaluronan. The ability of tumor cells to utilize anaerobic metabolism and to generate lactate, even in the presence of adequate supplies of oxygen, may be one of the mechanisms used to recruit host fibroblasts to deposit hyaluronan and to express CD44, thereby participating in the process of cancer invasion and metastasis. 相似文献