Participation of thrombospondin-1 in the activation of latent transforming growth factor-beta in malignant glioma cells.
Malignant glioma cells secrete transforming growth factor-beta (TGF-beta) and can activate latent TGF-beta. However, the mechanism of the latent TGF-beta activation has not yet been determined. This study examined whether thrombospondin-1 (TSP-1) secreted by malignant glioma cell lines participates in the activation of latent TGF-beta secreted by the glioma cells. Western blot analysis revealed that TSP-1 was present in both the cell lysates and the culture supernatants of all three malignant glioma cell lines (T98G, A172, and U251). A bioassay for TGF-beta activity revealed that all malignant glioma cell lines used in this study could activate latent TGF-beta by themselves. Latent TGF-beta 1 activation, evaluated by enzyme-linked immunosorbent assay, was inhibited by more than 50% by the addition of neutralizing anti-TSP-1 monoclonal antibody or anti-TSP-1 polyclonal antibody. These results indicate that TSP-1 has a predominant role in the activation of latent TGF-beta in malignant glioma cells.
Sasaki
A
A
Department of Neurosurgery, Yamanashi Medical University, Yamanashi.
Naganuma
H
H
Satoh
E
E
Kawataki
T
T
Amagasaki
K
K
Nukui
H
H
D014408:Biomarkers, Tumor; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D005910:Glioma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology*; D006801:Humans; D012333:RNA, Messenger / Q000032:analysis / Q000378:metabolism; D019700:Thrombospondin 1 / Q000235:genetics / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D014408:Biomarkers, Tumor; D012333:RNA, Messenger; D019700:Thrombospondin 1; D016212:Transforming Growth Factor beta