H Yamashita

Bone morphogenetic protein type IB receptor is progressively expressed in malignant glioma tumours.

The distribution of bone morphogenetic protein (BMP) type I receptors and the activin type I receptor (ActR-I) was investigated in 16 cases of human glioma and five cases of non-tumourous gliosis tissue by immunohistochemical technique. Both BMP type IA (BMPR-IA) and the type IB (BMPR-IB) receptors were detected in human glioma cells. A significant increase in BMPR-IB in tumour cells was observed in malignant glioma compared with both low-grade astrocytomas (n=16, P<0.005) and gliosis (n=13, P<0.001). However, enhancement of BMPR-IA staining was moderate and ActR-I staining was only weakly expressed in the malignant glioma tumours. Osteogenic protein (OP)-1/BMP-7, which is known to bind BMPR-IA, BMPR-IB and ActR-I, was expressed in nervous tissue and was also detected in anaplastic areas of malignant glioma. In contrast to the tissue materials, BMPR-IA was expressed to a stronger degree than BMPR-IB in human glioma cell lines; the growth of these cells was suppressed by OP-1. These results suggest the presence of BMP receptors and a functional role for BMPs in malignant glioma.

Regulation of Angiogenesis by TGF- β Superfamily

The angiogenesis process is regulated by many growth factors and cytokines, including transforming growth factor-beta (TGF-β) (1–3). The TGF-β superfamily, which contains the TGF-β family, the activin family, and the bone morphogenetic protein (BMP) family (4), exerts various effects on vascular cells. The effects of TGF-β differ between in vitro and in vivo (1–3). In this study, to investigate the mechanisms of regulation of angiogenesis by TGF-β superfamily members, angiogenic activity in vivo and the effects on cultured endothelial cells in vitro of TGF-β 1 activin A, and BMP-2 were examined.