HUMAN WILD-TYPE P53 INHIBITS CELL-PROLIFERATION AND ELICITS DRAMATIC MORPHOLOGICAL-CHANGES IN HUMAN GLIOMA CELL-LINES IN-VITRO

A human pilocytic astrocytoma-derived cell line, a grade III astrocyto ma-derived cell line, and a glioblastoma-derived cell line were transf ected with the human wild-type p53 gene, in order to demonstrate the p ossible suppressor role of this gene in low grade as well as in high g rade human astrocytomas. p53 exhibited a strong growth suppressor effe ct on the three cell lines studied, irrespective of the grade of malig nancy of the tumours from which they originate. Furthermore, the p53 g ene elicited important morphological changes in these cell lines. p53- Transfected cells displayed a flat morphology, a large cell body, and a stellate shape with long processes, characteristic of differentiated astrocytes. In addition, the growth inhibitory effect of p53 was foun d not to be due to induction of apoptosis. These results indicate that p53 plays a tumour suppressor role in low grade and high grade human astrocytomas and raise the possibility of the involvement of p53 in gl ioma cell differentiation in vitro.