Overexpression and localization of cathepsin B during the progression of human gliomas

✍ Scribed by Marupudi Sivaparvathi; Raymond Sawaya; Shang Wu Wang; Alan Rayford; Masaaki Yamamoto; Lance A. Liottat; Garth L. Nicolson; Jasti S. Rao

• Publisher: Springer
• Year: 1995
• Tongue: English
• Weight: 775 KB
• Volume: 13
• Category: Article
• ISSN: 0262-0898
• DOI: 10.1007/bf00144018

✦ Synopsis

Degradation of the extracellular matrix is a prerequisite for acquisition of the invasive phenotype. Several proteinases released by invading tumor cells appear to participate in the focal degradation of extracellular matrix proteins. Using an enzyme-linked immunosorbent assay, enzymatic assays, Western and Nothern blotting techniques, we determined whether increased levels of the cysteine protease cathepsin B correlated with the progression and invasion of human gliomas. The amount of cathepsin B activity and protein content were highest in glioblastomas, lower in anaplastic astrocytomas and lowest in normal brain tissue and low-grade gliomas. There were significantly higher amounts of Mr 25000 and 26000 bands in glioblastoma and anaplastic astrocytoma than in normal brain and low-grade glioma tissue extracts as determined by Western blotting with anti-cathepsin antibodies. In addition, cathepsin B transcripts were overexpressed in anaplastic astrocytoma (about two-to three-fold), in glioblastoma (about eight-to 10-fold), compared with normal brain tissue and low-grade glioma. Immunohistochemical staining for cathepsin B showed intense immunoreactivity in tumor and endothelial cells of glioblastomas and anaplastic astrocytomas but only weak immunoreactivity in low-grade glioma and normal brain tissues. Therefore, we conclude that cathepsin B expression is greatest in highly malignant astrocytomas, especially in glioblastomas, and is correlated with the malignant progression of astrocytomas.