ESTABLISHMENT OF SPONTANEOUSLY IMMORTALIZED RAT TYPE-1 ASTROGLIAL CELL-LINES - THE ROLE OF P53 IN ASTROGLIAL CARCINOGENESIS

We established five spontaneously immortalized cell lines using purifi ed rat type 1 astroglia on a rigid transfer schedule. All the cell lin es maintained their polygonal shape, regular pavement growth, low satu ration density, positive glial fibrillary acidic protein expression, a nd serum requirements, while none were tumorigenic in nude mice. We th en obtained a spontaneously transformed cell line by maintaining the c ells for 6 months at a high cell density. Since alterations of the tum or suppressor p53 gene have been reported in the immortalization of so me cell lines and in transformation of others, we characterized p53 in immortalized, spontaneously transformed, and 5 N-ethyl-N-nitrosourea (ENU)-transformed cell lines. While each of the ENU-induced or the spo ntaneously transformed cell lines exhibited p53 gene mutations that re sulted in amino acid alterations, no alterations in the p53 gene were observed in any of the immortalized cell lines. Thus, alterations of t he p53 protein correlate more strongly with transformation than with i mmortalization of type 1 astroglia. Immortalization may be regulated b y gene(s) other than p53. Spontaneously immortalized type 1 astroglial cell lines may provide a new tool to investigate an initial step of a stroglial carcinogenesis. (C) 1996 Wiley-Liss, Inc.