Quantification of thrombospondin-1 secretion and expression of ?v?3 and ?3?1 integrins and syndecan-1 as cell-surface receptors for thrombospondin-1 in malignant glioma cells

Abstract

Malignant glioma cells secrete thrombospondin-1 (TSP-1) which participates in the motility of glioma cells, and binds to cell surface alphavbeta3 and alpha3beta1 integrins, and syndecan-1. This study evaluated the amount of TSP-1 secretion from malignant glioma cells, and the expression of alphavbeta3 and alpha3beta1 integrins, and syndecan-1. The amounts of TSP-1 in the supernatants from 10 malignant glioma cell lines and eight non-glioma malignant tumor cell lines were measured by enzyme-linked immunosorbent assay. Expression of alphavbeta3 and alpha3beta1 integrins, and syndecan-1 were examined by flow cytometry. The amounts of TSP-1 secreted by malignant glioma cells were 43 to 2431 ng/l x 10(6) cells/24 h (mean +/- SD = 626 +/- 792). Seven of 10 glioma cell lines secreted more than 100 ng of TSP-1 and three of these cell lines secreted more than 1 microg. Seven of eight non-glioma cell lines secreted less than 100 ng of TSP-1. All glioma cell lines expressed alpha3beta1 integrin and syndecan-1, and seven of 10 glioma cell lines expressed alphavbeta3 integrin. Treatment of the glioma cell lines with TGF-beta2 did not change the expression of alphavbeta3 integrin. These results suggest that malignant glioma cells secrete high levels of TSP-1, which may be important in the migration of glioma cells via interactions with alphavbeta3 and alpha3beta1 integrins, and syndecan-1.

The role of syndecans in disease and wound healing

“…Syndecan-1 is expressed in various human cancers (Table 1; Bayer-Garner et al, 2000;Conejo et al, 2000;Harada et al, 2003;Naganuma et al, 2004;Sebestyen et al, 2000) and correlates with tumor recurrence in human prostate cancer (Chen et al, 2004a;Zellweger et al, 2003). Syndecan-1 is upregulated in human breast cancer samples compared to normal breast tissue, and in some breast cancer patients, increased syndecan-1 mRNA and protein correlate with higher histologic tumor grading, increased mitotic index, increased tumor size, and poor prognosis (Barbareschi et al, 2003;Tsanou et al, 2004).…”

Orthotopic pancreatic tumors detected by optoacoustic tomography using Syndecan-1

“…Partial in vitro binding (48.6%) was also observed with the positive control U251 cells, which are known to express high levels of α v β 3 (Figure 1). (13) In vivo binding was then assessed with traditional fluorescent imaging. Focal accumulation of syndecan-1 probe was evident early after injection, but was largely undetectable by 6h (Figure 2).…”

“…Bigner (Duke University, Durham, NC) to serve as the positive control for Syndecan-1 binding. (13) Cells were grown at 37° C and 5% CO 2 in Dulbecco’s modified Eagle medium (Life Technologies, Grand Island, NY) supplemented with 10% fetal bovine serum (Atlanta Biologicals, Lawrenceville, GA) and 1% L-glutamine (Life Technologies). S2VP10L cells containing fire-fly luciferase were used for in vivo experiments as previously described.…”

The Role of Clinical Proteomics, Lipidomics, and Genomics in the Diagnosis of Alzheimer’s Disease

“…Adiponectin has been shown to form protein complexes with alpha2-macroglobulin and thrombospondin-1 (TSP-1). Alterations in adiponectin levels determine alpha2–macroglobulin–amyloid beta interactions and TSP-1–amyloid beta interactions [124,125,126,127], which involve binding to cell receptors such as low-density lipoprotein receptor-related protein and heparin sulphate proteoglycans [128,129], showing a relationship between TSP-1 and amyloid beta in post-prandial lipid metabolism [37]. Adiponectin is important in astrocyte-neuron amyloid beta metabolism [1], with the effects of adiponectin on brain–liver amyloid clearance determined by proteins such as alpha 2 macroglobulin and TSP-1.…”