The surface properties of some human intracranial tumour cell lines in relation to their malignancy.

Abstract

The electronegativity of the surfaces of 8 human astrocytoma lines, 3 lines of meningioma, and one line of normal foetal brain cells, has been investigated using the isoelectric equilibrium method. The tumour cultures were initiated from human biopsy material and the foetal brain cell line was initiated from a 22-week-old human foetus. The protocols for the initiation and maintenance of the cultures are described. No changes in the surface isoelectric points (pI) of the cell lines occurred in relation to the time the cells had been maintained in culture. The pIs of the astrocytoma cell lines correlated extremely well with the malignancy of the tumours. The foetal brain cells showed the lowest pI, i.e. the highest net charge density, and in the increasing order of pI followed the highly malignant grade III and IV astrocytomas and the less malignant grade I and II astrocytomas. Meningiomas possessed an intermediate pI value. The experiments have also indicated that the more malignant astrocytomas possess surface coat material which appears to be susceptible to trypsinisation. Such material was not detected on the low-malignancy astrocytoma cells, the non-malignant meningiomas, or on foetal brain cells. It is suggested that this trypsin-labile surface coat material on the grade III and IV tumours may be associated with their malignancy. The surface charge densities of the astrocytoma and foetal brain cell lines also correlated with their growth rates.