Malignant properties of P635 glioma are independent of glial fibrillary acidic protein expression

Abstract

To examine the relationship between the malignant behavior of rat glioma cells and expression of the differentiation antigen glial fibrillary acidic protein (GF), we assayed the tumorigenicity and metastatic ability of P635 and its GF+ or GF- clones. We injected P635 (GF+) and clone 45 (GF-) cells intramuscularly in nude mice. Both lines formed local tumors which metastasized to lungs with equal efficiency. We then injected these lines intravenously in nude mice. Both produced experimental metastases in lungs and other organs with equal efficiency. Finally we injected P635 and several GF+ and GF- clones into the chorioallantoic membrane veins of naturally immune-deficient chick embryos and measured cell growth in embryonic liver. We again found that all clones survived and grew equally well. P635 cells are capable of extracranial growth and metastasis, two important features of the malignant phenotype. We conclude that GF in P635 is a neutral marker with respect to tumorigenicity and metastatic ability.

Human and Rat Glioma Growth, Invasion, and Vascularization in a Novel Chick Embryo Brain Tumor Model

“…The chick embryo has been used previously to study properties of mammalian tumor cells, including gliomas, but this has almost exclusively been in the context of metastasis to distant sites or vascularization of the tumors. For example, Chambers and co-workers have injected glioma and other tumor cells into veins of the chorioallantoic membrane (CAM) to demonstrate their metastatic potential [6,7]. Another study grafted surgical glioma specimens onto the chick CAM and assessed their chemosensitivity to anticancer drugs [21].…”

“…A few studies have been done by others in chicken embryos, but the primary focus was to demonstrate metastatic potential [e.g. 6,7] and not to describe local invasiveness in the brain. We previously oncogenically transformed cells in the embryonic chick brain with forms of the v-src oncogene [8], and this suggested to us that such an environment might be suitable for growth of existing mammalian brain tumor cell lines.…”

Glioma Cell Biology

“…A few investigators have also used xenografts in chicken embryos to study tumor cell behavior (Chambers et al 1990(Chambers et al , 1991. Cretu and colleagues used established rat glioma cell lines (U-87, C6, and 9L) and injected them into the ventricles of the chicken embryos (Cretu et al 2005).…”