Glycosaminoglycan chains from α5β1 integrin are involved in fibronectin-dependent cell migrationDedicated to the memory of Professor Carl P. Dietrich.

2009 ◽  
Vol 87 (4) ◽  
pp. 677-686 ◽  
Author(s):  
Célia R.C. Franco ◽  
Edvaldo S. Trindade ◽  
Hugo A.O. Rocha ◽  
Rafael Bertoni da Silveira ◽  
Katia Sabrina Paludo ◽  
...  

α5β1 integrin from both wild-type CHO cells (CHO-K1) and deficient in proteoglycan biosynthesis (CHO-745) is post-translationally modified by glycosaminoglycan chains. We demonstrated this using [35S]sulfate metabolic labeling of the cells, enzymatic degradation, immunoprecipitation reaction with monoclonal antibody, fluorescence microscopy, and flow cytometry. The α5β1 integrin heterodimer is a hybrid proteoglycan containing both chondroitin and heparan sulfate chains. Xyloside inhibition of sulfate incorporation into α5β1 integrin also supports that integrin is a proteoglycan. Also, cells grown with xyloside adhered on fibronectin with no alteration in α5β1 integrin expression. However, haptotactic motility on fibronectin declined in cells grown with xyloside or chlorate as compared with controls. Thus, α5β1 integrin is a proteoglycan and the glycosaminoglycan chains of the integrin influence cell motility on fibronectin. Similar glycosylation of α5β1 integrin was observed in other normal and malignant cells, suggesting that this modification is conserved and important in the function of this integrin. Therefore, these glycosaminoglycan chains of α5β1 integrin are involved in cellular migration on fibronectin.

2020 ◽  
Vol 20 (16) ◽  
pp. 1895-1907
Author(s):  
Navgeet Kaur ◽  
Anju Goyal ◽  
Rakesh K. Sindhu

The importance of monoclonal antibodies in oncology has increased drastically following the discovery of Milstein and Kohler. Since the first approval of the monoclonal antibody, i.e. Rituximab in 1997 by the FDA, there was a decline in further applications but this number has significantly increased over the last three decades for various therapeutic applications due to the lesser side effects in comparison to the traditional chemotherapy methods. Presently, numerous monoclonal antibodies have been approved and many are in queue for approval as a strong therapeutic agent for treating hematologic malignancies and solid tumors. The main target checkpoints for the monoclonal antibodies against cancer cells include EGFR, VEGF, CD and tyrosine kinase which are overexpressed in malignant cells. Other immune checkpoints like CTLA-4, PD-1 and PD-1 receptors targeted by the recently developed antibodies increase the capability of the immune system in destroying the cancerous cells. Here, in this review, the mechanism of action, uses and target points of the approved mAbs against cancer have been summarized.


Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 341-350
Author(s):  
Jean T Greenberg ◽  
F Paul Silverman ◽  
Hua Liang

Abstract Salicylic acid (SA) is required for resistance to many diseases in higher plants. SA-dependent cell death and defense-related responses have been correlated with disease resistance. The accelerated cell death 5 mutant of Arabidopsis provides additional genetic evidence that SA regulates cell death and defense-related responses. However, in acd5, these events are uncoupled from disease resistance. acd5 plants are more susceptible to Pseudomonas syringae early in development and show spontaneous SA accumulation, cell death, and defense-related markers later in development. In acd5 plants, cell death and defense-related responses are SA dependent but they do not confer disease resistance. Double mutants with acd5 and nonexpressor of PR1, in which SA signaling is partially blocked, show greatly attenuated cell death, indicating a role for NPR1 in controlling cell death. The hormone ethylene potentiates the effects of SA and is important for disease symptom development in Arabidopsis. Double mutants of acd5 and ethylene insensitive 2, in which ethylene signaling is blocked, show decreased cell death, supporting a role for ethylene in cell death control. We propose that acd5 plants mimic P. syringae-infected wild-type plants and that both SA and ethylene are normally involved in regulating cell death during some susceptible pathogen infections.


2010 ◽  
Vol 30 (5) ◽  
pp. 1031-1043 ◽  
Author(s):  
Longxuan Li ◽  
Jennifer V Welser ◽  
Richard Milner

Cerebral angiogenesis is an important adaptive response to hypoxia. As the αvβ3 integrin is induced on angiogenic vessels in the ischemic central nervous system (CNS), and the suggested angiogenic role for this integrin in other systems, it is important to determine whether the αvβ3 integrin is an important mediator of cerebral angiogenesis. αvβ3 integrin expression was examined in a model of cerebral hypoxia, in which mice were subject to hypoxia (8% O2) for 0, 4, 7, or 14 days. Immunofluorescence and western blot analysis revealed that in the hypoxic CNS, αvβ3 integrin was strongly induced on angiogenic brain endothelial cells (BEC), along with its ligand vitronectin. In the hypoxia model, β3 integrin-null mice showed no obvious defect in cerebral angiogenesis. However, early in the angiogenic process, BEC in these mice showed an increased mitotic index that correlated closely with increased α5 integrin expression. In vitro experiments confirmed α5 integrin upregulation on β3 integrin-null BEC, which also correlated with increased BEC proliferation on fibronectin. These studies confirm hypoxic induction of αvβ3 integrin on angiogenic vessels, but suggest distinct roles for the BEC integrins αvβ3 and α5β1 in cerebral angiogenesis, with αvβ3 having a nonessential role, and α5β1 promoting BEC proliferation.


2008 ◽  
Vol 364 (1514) ◽  
pp. 269-276 ◽  
Author(s):  
Timothy J Nelson ◽  
Almudena Martinez-Fernandez ◽  
Andre Terzic

KCNJ11 -encoded Kir6.2 assembles with ATP-binding cassette sulphonylurea receptors to generate ATP-sensitive K + (K ATP ) channel complexes. Expressed in tissues with dynamic metabolic flux, these evolutionarily conserved yet structurally and functionally unique heteromultimers serve as high-fidelity rheostats that adjust membrane potential-dependent cell functions to match energetic demand. Genetic defects in channel subunits disrupt the cellular homeostatic response to environmental stress, compromising organ tolerance in the adult. As maladaptation characterizes malignant K ATP channelopathies, establishment of platforms to examine progression of K ATP channel-dependent adaptive behaviour is warranted. Chimeras provide a powerful tool to assay the contribution of genetic variance to stress intolerance during prenatal or post-natal development. Here, KCNJ11 K ATP channel gene knockout↔wild-type chimeras were engineered through diploid aggregation. Integration of wild-type embryonic stem cells into zona pellucida-denuded morula derived from knockout embryos achieved varying degrees of incorporation of stress-tolerant tissue within the K ATP channel-deficient background. Despite the stress-vulnerable phenotype of the knockout, ex vivo derived mosaic blastocysts tolerated intrauterine transfer and implantation, followed by full-term embryonic development in pseudopregnant surrogates to produce live chimeric offspring. The development of adult chimerism from the knockout↔wild-type mosaic embryo offers thereby a new paradigm to probe the ecogenetic control of the K ATP channel-dependent stress response.


Blood ◽  
2011 ◽  
Vol 117 (18) ◽  
pp. 4978-4987 ◽  
Author(s):  
Elzbieta Pluskota ◽  
James J. Dowling ◽  
Natalie Gordon ◽  
Jeffrey A. Golden ◽  
Dorota Szpak ◽  
...  

Abstract Kindlin-2, a widely distributed cytoskeletal protein, has been implicated in integrin activation, and its absence is embryonically lethal in mice and causes severe developmental defects in zebrafish. Knockdown of kindlin-2 levels in endothelial cells resulted in defective adhesive and migratory responses, suggesting that angiogenesis might be aberrant even with partial reduction of kindlin-2. This hypothesis has now been tested in the kindlin-2+/− mice. RM1 prostate tumors grown in kindlin-2+/− mice had fewer blood vessels, which were thinner and shorter and supported less tumor growth compared with wild-type littermates. The vessels that did form in the kindlin-2+/− mice lacked smooth muscle cells and pericytes and had thinner basement membranes, indicative of immature vessels. VEGF-induced angiogenesis in matrigel implants was also abnormal in the kindlin-2+/− mice. Vessels in the kindlin-2+/− mice were leaky, and BM transplantation from kindlin-2+/− to WT mice did not correct this defect. Endothelial cells derived from kindlin-2+/− mice had integrin expression levels similar to WT mice but reduced αVβ3-dependent signaling, migration, adhesion, spreading, and tube formation. Developmental angiogenesis was markedly impaired by kindlin-2 morpholinos in zebrafish. Taken together, kindlin-2 plays an important role in pathologic and developmental angiogenesis, which arises from defective activation of integrin αVβ3.


Blood ◽  
1990 ◽  
Vol 76 (7) ◽  
pp. 1361-1368
Author(s):  
WB Labastide ◽  
MT Rana ◽  
CR Barker

We describe a new rat immunoglobulin M monoclonal antibody (CH-F42) that recognizes a subset (1.5% to 8%) of normal peripheral blood T lymphocytes. The phenotype of these cells was determined, using dual- color immunofluorescence, to be CD2+, CD3+, CD4+, CD5+, CD7-, CD8-. They do not express T-cell activation markers, and are positive for UCHL1 (CD45RO), but negative for 2H4 (CD45RA). The antigen was expressed on circulating malignant cells in Sezary syndrome (four of four cases) and adult T-cell lymphoma-leukemia (ATLL) (four of six cases) and negative in a variety of other hematologic malignancies tested. These included chronic and acute lymphoid leukemias of B and T lineage, together with chronic and acute myeloid leukemias. However, normal CH-F42+ cells do not display any of the ultrastructural features associated with Sezary or ATLL cells. The marked similarities between these conditions together with the shared expression of an otherwise very restricted surface antigen (CH-F42) provide strong evidence for the existence of a common normal counterpart. Preliminary characterization studies of the antigen, which is also expressed by K562 and Jurkat cells, suggest the CH-F42 antigen is an O-linked, sialated glycan on a glycoprotein.


2003 ◽  
Vol 56 (9) ◽  
pp. 841 ◽  
Author(s):  
Lutz F. Tietze ◽  
Tim Feuerstein

Antibody-directed enzyme prodrug therapy (ADEPT) is a recent development for a selective treatment of cancer, based on site-directed formation at the surface of malignant cells of cytotoxic compounds from non-toxic prodrugs with a conjugate of an appropriate enzyme and a monoclonal antibody which binds to tumour-associated antigens. New potent prodrugs of analogues of the antibiotic CC-1065 have been developed. These show a remarkable selectivity with a Q(IC50) value of up to more than 3000. Moreover, the formed drug has a high potency with an IC50 of 30 pM.


2016 ◽  
Vol 85 (1) ◽  
Author(s):  
William E. Sause ◽  
Daniela Keilberg ◽  
Soufiane Aboulhouda ◽  
Karen M. Ottemann

ABSTRACT The human pathogen Helicobacter pylori uses the host receptor α5β1 integrin to trigger inflammation in host cells via its cag pathogenicity island (cag PAI) type IV secretion system (T4SS). Here, we report that the H. pylori ImaA protein (HP0289) decreases the action of the cag PAI T4SS via tempering the bacterium's interaction with α5β1 integrin. Previously, imaA-null mutants were found to induce an elevated inflammatory response that was dependent on the cag PAI T4SS; here we extend those findings to show that the elevated response is independent of the CagA effector protein. To understand how ImaA could be affecting cag PAI T4SS activity at the host cell interface, we utilized the Phyre structural threading program and found that ImaA has a region with remote homology to bacterial integrin-binding proteins. This region was required for ImaA function. Unexpectedly, we observed that imaA mutants bound higher levels of α5β1 integrin than wild-type H. pylori, an outcome that required the predicted integrin-binding homology region of ImaA. Lastly, we report that ImaA directly affected the amount of host cell β1 integrin but not other cellular integrins. Our results thus suggest a model in which H. pylori employs ImaA to regulate interactions between integrin and the T4SS and thus alter the host inflammatory strength.


1987 ◽  
Vol 87 (1) ◽  
pp. 121-132
Author(s):  
K. Toda ◽  
D. Francis ◽  
G. Gerisch

Binding of a monoclonal antibody, mAb293, to cell-surface glycoproteins of Polysphondylium pallidum is known to be blocked by L-fucose, and Fab of this antibody has been shown to inhibit intercellular adhesion of aggregation-competent cells. Mutants with delayed expression of the carbohydrate epitope, ep293, recognized by the antibody, have been shown to be retarded and altered in cell aggregation. The present study shows that ep293 is a modification of carbohydrate structure that is subject to regulation not only in mutant but also in wild-type cells; ep293 is expressed at an early stage of exponential growth in wild-type and only after 12 h of starvation in mutant PN6002. Proteins are already glycosylated before the epitope is expressed. The developmental regulation of pallidin, a lectin known to be an unglycosylated protein, was investigated in parallel with ep293 using a monoclonal antibody. Pallidin was expressed at about the same time as the carbohydrate epitope in cells of the wild-type as well as the mutant. These results indicate a regulatory signal to which various events are coupled. Induction of ep293 and expression of pallidin are two of these events, and mutants such as PN6002 are altered in the timing of the signal.


Sign in / Sign up

Export Citation Format

Share Document