Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0017638 (glioma)
 30,880 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The expression of platelet-derived growth factor (PDGF) and its receptors was analyzed in 14 gliomas of various degrees of malignancy and compared with three gliosis cases by in situ hybridization and immunohistochemistry techniques. Expression of both PDGF A- and B-chains was higher in glioblastomas than in astrocytomas. The PDGF A-chain mRNA was predominantly found in cell-rich areas in glioblastomas. The cognate PDGF-alpha receptor (PDGFR-alpha) mRNA was heterogeneously distributed in gliomas of all grades, and PDGFR-alpha expression was higher in gliomas than in gliosis. Within some glioblastomas probed with PDGFR-alpha complementary RNA, cells heavily loaded with grains were intermingled with others containing low or moderate signals. The heavily labeled cells were often found in the vicinity of proliferating capillaries. Immunostaining with an anti-PDGF antibody and an affinity-purified antiserum against the PDGFR-alpha showed strong staining of most tumor cells with both antibodies in glioblastoma. In addition, the PDGFR-alpha antibodies yielded a strong staining of scattered cells, and the anti-PDGF antibody yielded staining of a few cells within the astrocytoma. Furthermore, high levels of the PDGF-beta receptor (PDGFR-beta) and PDGF B-chain mRNA as well as the beta receptor protein were found in hyperplastic capillaries. These results suggest the presence of autocrine and paracrine loops in glioma, activating the PDGFR-alpha in glioma cells and the PDGFR-beta in endothelial cells.
 ...
PMID:Platelet-derived growth factor and its receptors in human glioma tissue: expression of messenger RNA and protein suggests the presence of autocrine and paracrine loops. 131 61

We report herein the presence of a 56 kd platelet derived growth factor (PDGF)-related protein as a phosphorylated form in human glioma cells. The phosphorylation of the 56 kd form was found to be the longest of all PDGF-related proteins. By Western blotting using a monoclonal anti-PDGF B-chain, the 80 kd, 56 kd, 40 kd, 28 kd and 17 kd PDGF-related proteins were detected, while after treatment among the nitrocellulose membrane transblotted cell extracts with alkaline phosphatase, 40 kd was the most densely observed while the 56 kd and 80 kd PDGF-related proteins were also detected. In a 32P flush labeling study, it was revealed that PDGF-related proteins incorporated with 32P were detected at 28, 32, 35, 40, 56 and 80 kd but the 17 kd monomer was not labeled. Among the labeled PDGF-related proteins, the 56 kd PDGF-related protein alone remained intracellularly for at least 16 hours. These results indicated that the PDGF-related proteins in human glioma cells are synthesized in a phosphorylated form and partly remain in a 56 kd phosphorylated form intracellularly. The 56 kd form may thus be the most stable form and likely has a substantial biological effect.
 ...
PMID:The 56 kd platelet-derived growth factor (PDGF)-related protein is phosphorylated and the most stable form in human glioma cells. 143 29

Platelet-derived growth factor (PDGF) is a potent mitogen for a variety of cell types. PDGF is made up as dimers of A and B polypeptide chains which are combined to generate the three isoforms of PDGF (AA, AB, BB). These bind with different specificities and affinities to two types of cell surface receptors (the alpha-receptor and the beta-receptor), both being members of the protein tyrosine kinase family of growth factor receptors. A number of human tumor cell lines, particularly those established from glioma and sarcoma, have been shown to produce PDGF and express the cognate receptor type. In these instances, tumor cell growth may be enhanced by an autocrine receptor activation. In other tumor cell types, where PDGF is produced in the absence of receptor expression, the growth factor may act in a paracrine fashion. This view is supported by our recent finding that human melanoma cells that have been stably transfected with a PDGF B-chain cDNA, elicit a stroma response when transplanted to nude mice.
 ...
PMID:Platelet-derived growth factor. Structure, function and implications in normal and malignant cell growth. 832 51