Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathogenic Neisseriae Neisseria meningitidis and Neisseria gonorrhoeae, initiate colonization by attaching to host cells using type IV pili. Subsequent adhesive interactions are mediated through the binding of other bacterial adhesins, in particular the Opa family of outer membrane proteins. Here, we have shown that pilus-mediated adhesion to host cells by either meningococci or gonococci triggers the rapid, localized formation of dramatic cortical plaques in host epithelial cells. Cortical plaques are enriched in both components of the cortical cytoskeleton and a subset of integral membrane proteins. These include: CD44v3, a heparan sulphate proteoglycan that may serve as an Opa receptor; EGFR, a receptor tyrosine kinase; CD44 and ICAM-1, adhesion molecules known to mediate inflammatory responses; f-actin; and ezrin, a component that tethers membrane components to the actin cytoskeleton. Genetic analyses reveal that cortical plaque formation is highly adhesin specific. Both pilE and pilC null mutants fail to induce cortical plaques, indicating that neisserial type IV pili are required for cortical plaque induction. Mutations in pilT, a gene required for pilus-mediated twitching motility, confer a partial defect in cortical plaque formation. In contrast to type IV pili, many other neisserial surface structures are not involved in cortical plaque induction, including Opa, Opc, glycolipid GgO4-binding adhesins, polysialic acid capsule or a particular lipooligosaccharide variant. Furthermore, it is shown that type IV pili allow gonococci to overcome the inhibitory effect of heparin, a soluble receptor analogue, on gonococcal invasion of Chang and A431 epithelial cells. These and other observations strongly suggest that type IV pili play an active role in initiating neisserial infection of the mucosal surface in vivo. The functions of type IV pili and other neisserial adhesins are discussed in the specific context of the mucosal microenvironment, and a multistep model for neisserial colonization of mucosal epithelia is proposed.
Mol Microbiol 1999 Jun
PMID:Type IV pili of pathogenic Neisseriae elicit cortical plaque formation in epithelial cells. 1038 71

One of the most important features of tumor cell invasion is the ability to establish or modulate adhesion to other cells or to an extracellular matrix, a process mediated by a large number of adhesion proteins. This review examines how CD44 participates in malignant transformation and progression of the breast epithelium. CD44 is a family of cell adhesion glycoproteins generated by alternative splicing of up to 10 variant exons. Discrete CD44 isoforms are overexpressed in different human cancers, including breast cancer. Recent studies, including our own, have shown that CD44 is involved in two of the three steps of the invasive cascade: adhesion to the extracellular matrix and motility. The overexpression of one of the CD44 variants, CD44v6, is a significant component in the malignant transformation of the breast epithelium and its use as a prognostic marker is presently investigated.
Exp Mol Pathol 1999 Jun
PMID:Adhesion proteins in the biology of breast cancer: contribution of CD44. 1040 43

CD44, an integral membrane glycoprotein expressed by many cell types, serves as the principal transmembrane hyaluronate receptor and might be a determinant of metastatic and invasive behaviour in carcinomas. The generation of CD44 splice variants might be linked closely with gastric carcinoma tumorigenesis and differentiation. Some studies have reported that the magnitude of CD44 variant synthesis at the protein level correlates with lymph node metastasis. A number of studies have examined the possible mechanism of involvement of the CD44 variant in tumour metastasis. Most studies have reported that the regulation of CD44 binding to hyaluronate results from glycosylation of variably spliced exons. Direct hyaluronate binding studies of CD44 V4-V7 isoforms transfected into the human gastric carcinoma cell line, SC-M1, have indicated that the V4-V7 isoforms themselves, in addition to glycosylation, can alter hyaluronate binding.
Mol Pathol 1999 Feb
PMID:Molecular studies into the role of CD44 variants in metastasis in gastric cancer. 1043 35

Background: Abnormal expression of CD44 variant RNA has been detected in a variety of human tumors and has been shown to be a potential diagnostic marker. To date, such analysis requires time-consuming gel electrophoresis, blotting, and autoradiographic procedures, and this approach may not be suitable for routine laboratory examinations. We have developed a rapid and semiquantitative reverse transcription-polymerase chain reaction enzyme-linked immunosorbent assay (RT-PCR ELISA) method and used it to analyze CD44 expression in colon carcinoma tissues and exfoliated cancer cells in colon luminal washings. Methods and Results: RNA was extracted from sample cells and tissues and converted to cDNA. PCR amplification products, labeled by incorporation of digoxigenin-11-dUTP, were hybridized with biotinylated probes complementary to CD44 exon 12 or to exons in the standard portion (CD44s) of the gene. Hybridized DNA complexes were immobilized on streptavidin-coated microtiter plates, and the bound PCR products were detected with a peroxidase-conjugated antibody to digoxigenin. CD44-derived PCR products were quantified by absorbance of a chromogenic reaction. Elevated expression of CD44 variant exon 12 was detected initially by Southern blot analysis in all of the 9 colon carcinoma tissues, while weak expression was observed in only 3 of 9 normal mucosas. This tumor-related differential expression was confirmed by the newly developed PCR-ELISA method. Elevated expression of CD44 exon 12 was also detected in exfoliated colonic epithelial cells from 10 of 13 carcinoma cases but not in exfoliated cells from 4 patients with inflammatory bowel disease. Conclusions: Raised expression of CD44 variant exon transcripts can be detected reliably in colonic tumor tissue and in exfoliated colonic cancer cells by a semiquantitative RT-PCR ELISA method. This was shown to be as sensitive as conventional RT-PCR using chemiluminescent detection. Therefore, CD44-based RT-PCR ELISA could facilitate detection of neoplasia in clinical specimens including colon washings and naturally micturated urine.
Mol Diagn 1996 Sep
PMID:Semiquantitative Detection of Abnormal CD44 Transcripts in Colon Carcinomas by Reverse Transcription-Polymerase Chain Reaction Enzyme-linked Immunosorbant Assay (RT-PCR ELISA). 1046 57

Background: Disorderly expression of the CD44 gene is a characteristic feature of many common types of human malignancy. The explanation for the diversity, abundancy, and abnormally large size of the resulting transcripts is under investigation. Methods and Results: This study used reverse transcription-polymerase chain reaction (RT-PCR)/Southern blot hybridization to examine the expression of the CD44 gene in fresh tissue samples from 21 breast cancers and 11 matched non-neoplastic breast tissue specimens from the same patients. Using probes for several exons and for a noncoding region (intron 9) of the gene, it was found that the previously described elevated levels of CD44 transcripts in malignant tumors of this organ include many unusual, alternatively spliced isotypes as well as immature forms that retain this intron and probably several others. All of the exons that were tested were involved in the disorderly overexpression of this gene observed in all of the cancer tissues, and we were able to detect retention of the intron 9 sequence in 14 (67%) of the 21 tumor samples. In contrast, it was possible to detect signals in only 3 (27%) of the 11 samples from nonmalignant breast tissue with this probe, and these were extremely faint. Conclusions: These findings imply that there is a profound disorder in the regulation of production, splicing, and processing of CD44 pre-mRNA in breast cancer tissues comparable to that described in tumors of many other organs. The clinical implication of this information is that analysis of tissue samples containing borderline or suspected premalignant lesions for the presence of these molecular abnormalities, which appear to be characteristic of neoplasia, may in due course help assessment of individual patient prognosis and optimization of treatment.
Mol Diagn 1996 Sep
PMID:Accumulation of Immature Intron-containing CD44 Gene Transcripts in Breast Cancer Tissues. 1046 58

Background: CD44, a major cell surface receptor for hyaluronic acid, is a family of ubiquitous cell surface glycoproteins. Altered levels of CD44 expression, seen in many epithelial neoplasms, have prognostic implications. Expression of standard and variant isoforms of CD44 was assessed in normal and neoplastic human prostate tissue and culture cells to evaluate as a marker for malignant transformation. Methods and Results: Expression of CD44s, CD44R, v5, v6, v7/8 and v10 was assessed in prostate tissue (benign and malignant) and cell lines (DU-145, PC-3, LNCaP, p69) and primary cultures of normal prostates and adenocarcinoma cells obtained from prostatectomies using reverse transcriptor polymerase chain reaction, Western blotting, and immunofluorescence. No CD44 expression was seen in LNCaP cells. p69, DU-145, and PC-3 cells expressed CD44s and CD44R. p69, cells demonstrated a 1000-bp-long form of CD44 mRNA, unique to this normal cell line. Both normal and neoplastic prostatic tissue demonstrated CD44s on Western blotting. Conclusions: In agreement with previous studies, prostatic adenocarcinoma cells, except LNCaP, expressed CD44s. Different patterns of CD44 expression were seen in benign and neoplastic prostate. Benign prostate exhibited higher v5 protein levels, whereas neoplastic prostates demonstrated higher CD44s expression. CD44s expression was identified in all neoplastic prostates as compared with only 50% of the benign prostates. No significant difference in expression of the other variants assessed (v6, v7, v7/8, and v10) was observed in the benign and neoplastic prostates.
Mol Diagn 1997 Sep
PMID:CD44 Expression in Benign and Neoplastic Human Prostates. 1046 10

Haptokinetic cell migration across surfaces is mediated by adhesion receptors including beta1 integrins and CD44 providing adhesion to extracellular matrix (ECM) ligands such as collagen and hyaluronan (HA), respectively. Little is known, however, about how such different receptor systems synergize for cell migration through three-dimensionally (3-D) interconnected ECM ligands. In highly motile human MV3 melanoma cells, both beta1 integrins and CD44 are abundantly expressed, support migration across collagen and HA, respectively, and are deposited upon migration, whereas only beta1 integrins but not CD44 redistribute to focal adhesions. In 3-D collagen lattices in the presence or absence of HA and cross-linking chondroitin sulfate, MV3 cell migration and associated functions such as polarization and matrix reorganization were blocked by anti-beta1 and anti-alpha2 integrin mAbs, whereas mAbs blocking CD44, alpha3, alpha5, alpha6, or alphav integrins showed no effect. With use of highly sensitive time-lapse videomicroscopy and computer-assisted cell tracking techniques, promigratory functions of CD44 were excluded. 1) Addition of HA did not increase the migratory cell population or its migration velocity, 2) blocking of the HA-binding Hermes-1 epitope did not affect migration, and 3) impaired migration after blocking or activation of beta1 integrins was not restored via CD44. Because alpha2beta1-mediated migration was neither synergized nor replaced by CD44-HA interactions, we conclude that the biophysical properties of 3-D multicomponent ECM impose more restricted molecular functions of adhesion receptors, thereby differing from haptokinetic migration across surfaces.
Mol Biol Cell 1999 Oct
PMID:Functional hierarchy of simultaneously expressed adhesion receptors: integrin alpha2beta1 but not CD44 mediates MV3 melanoma cell migration and matrix reorganization within three-dimensional hyaluronan-containing collagen matrices. 1051 51

The CD44 proteins form a ubiquitously expressed family of cell surface adhesion molecules involved in cell-cell and cell-matrix interactions. The multiple protein isoforms are encoded by a single gene by alternative splicing and are further modified by a range of post-translational modifications. CD44 proteins are single chain molecules comprising an N-terminal extracellular domain, a membrane proximal region, a transmembrane domain, and a cytoplasmic tail. The CD44 gene has only been detected in higher organisms and the amino acid sequence of most of the molecule is highly conserved between mammalian species. The principal ligand of CD44 is hyaluronic acid, an integral component of the extracellular matrix. Other CD44 ligands include osteopontin, serglycin, collagens, fibronectin, and laminin. The major physiological role of CD44 is to maintain organ and tissue structure via cell-cell and cell-matrix adhesion, but certain variant isoforms can also mediate lymphocyte activation and homing, and the presentation of chemical factors and hormones. Increased interest has been directed at the characterisation of this molecule since it was observed that expression of multiple CD44 isoforms is greatly upregulated in neoplasia. CD44, particularly its variants, may be useful as a diagnostic or prognostic marker of malignancy and, in at least some human cancers, it may be a potential target for cancer therapy. This review describes the structure of the CD44 gene and discusses some of its roles in physiological and pathological processes.
Mol Pathol 1999 Aug
PMID:CD44 cell adhesion molecules. 1069 38

Progesterone inhibits the proliferation of normal breast epithelial cells in vivo, as well as breast cancer cells in vitro. But the biologic mechanism of this inhibition remains to be determined. We explored the possibility that an antiproliferative activity of progesterone in breast cancer cell lines is due to its ability to induce apoptosis. Since p53, bcl-2 and survivin genetically control the apoptotic process, we investigated whether or not these genes could be involved in the progesterone-induced apoptosis. We found a maximal 90% inhibition of cell proliferation with T47-D breast cancer cells after exposure to 10 microM progesterone for 72 h. Control progesterone receptor negative MDA-231 cancer cells were unresponsive to 10 microM progesterone. The earliest sign of apoptosis is translocation of phosphatidylserine from the inner to the outer leaflet of the plasma membrane and can be monitored by the calcium-dependent binding of annexin V in conjunction with flow cytometry. After 24 h of exposure to 10 microM progesterone, cytofluorometric analysis of T47-D breast cancer cells indicated 43% were annexin V-positive and had undergone apoptosis and no cells showed signs of cellular necrosis (propidium iodide negative). After 72 h of exposure to 10 microM progesterone, 48% of the cells had undergone apoptosis and 40% were annexin V positive/propidium iodide positive indicating signs of necrosis. Control untreated cancer cells did not undergo apoptosis. Evidence proving apoptosis was also demonstrated by fragmentation of nuclear DNA into multiples of oligonucleosomal fragments. After 24 h of exposure of T47-D cells to either 1 or 10 microM progesterone, we observed a marked down-regulation of protooncogene bcl-2 protein and mRNA levels. mRNA levels of survivin and the metastatic variant CD44 v7-v10 were also downregulated. Progesterone increased p53 mRNA levels. These results demonstrate that progesterone at relative high physiological concentrations, but comparable to those seen in plasma during the third trimester of human pregnancy, exhibited a strong antiproliferative effect on breast cancer cells and induced apoptosis.
Mol Cell Biochem 1999 Dec
PMID:Bcl-2, survivin and variant CD44 v7-v10 are downregulated and p53 is upregulated in breast cancer cells by progesterone: inhibition of cell growth and induction of apoptosis. 1070 95

The receptors for interleukin-3 (IL-3) and granulocyte-macrophage colony-stimulating factor (GM-CSF) share a common beta subunit, the distal cytoplasmic domain of which is essential for the promotion of cell survival by these two cytokines. Genes whose expression is specifically induced by signaling through the distal cytoplasmic domain of this receptor beta subunit were screened by a subtraction cloning approach in derivatives of a mouse pro-B-cell line. One gene thus identified was shown to encode a protein highly homologous (with only 7 amino acid substitutions) to murine osteopontin (OPN), a secreted adhesion protein. Conditioned medium from cells expressing wild-type OPN, but not that from cells expressing a deletion mutant lacking residues 79 to 140, increased the viability of a non-OPN-producing cell line in the presence of human GM-CSF. Antibody blocking experiments revealed that OPN produced as a result of IL-3 or GM-CSF signaling was secreted into the medium and, through binding to its cell surface receptor, CD44, contributed to the survival-promoting activities of these two cytokines. Furthermore, coupling of the OPN-CD44 pathway to the survival response to IL-3 was also demonstrated in primary IL-3-dependent mouse bone marrow cells. These results thus show that induction of an extracellular adhesion protein and consequent activation of its cell surface receptor are important for the antiapoptotic activities of IL-3 and GM-CSF.
Mol Cell Biol 2000 Apr
PMID:Coupling of osteopontin and its cell surface receptor CD44 to the cell survival response elicited by interleukin-3 or granulocyte-macrophage colony-stimulating factor. 1073 76


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