Establishment and characterization of a novel malignant astrocytoma cell line derived from a tumor removed in a patient with neurofibromatosis Type 1

Object. Patients with neurofibromatosis Type 1 (NF1) have a predisposition to development of a variety of benign and malignant tumors including neurof ibromas, astrocytomas, pheochromocytomas, and malignant peripheral nerve sh eath tumors. The availability of an astrocytoma cell line derived from NF1 would be useful in studies in which sporadic astrocytomas could be compared with NF1-derived astrocytomas. In this article the authors describe a nove l astrocytoma cell line, TM-31, that they established from a tumor removed in a 42-year-old woman with NF1. Methods. The TM-31 cell line was prepared from a surgical specimen of malig nant astrocytoma and was serially subcultured over 250 times throughout a 6 -year period without showing any sign of cell senescence. Immunocytochemica l analyses demonstrated that TM-31 cells are negative for glial fibrillary acidic protein but positive for vimentin and S-100 protein. The TM-31 cells display little neurofibromin expression when subjected to immunoblotting, indicating that there is an NF1 gene mutation. Polymerase chain reaction-si ngle-strand conformational polymorphism analysis revealed that TM-31 cells harbor a p53 point mutation in exon 7, codon 238. Chemosensitivity testing of TM-31 cells revealed a resistance to 1-(4-amino-2-methyl-5-pyrimidinyl)m ethyl-3-nitrosourea, although they are sensitive to cisplatin and etoposide . In addition, TM-31 cells displayed no morphological differentiation after all-transretinoic acid and dibutyryl cyclic adenosine monophosphate treatm ents. Pharmacological inhibition of farnesyltransferase of the Ras oncoprot ein led to decreased proliferative activity and inhibition of anchorage-ind ependent growth of TM-31 cells in soft agar. Conclusions. The TM-31 cell line is an immortalized astrocytoma cell line d erived from a tumor obtained in a patient with NF1. Ras activation may be t he major event of proliferative activity and of the transformed phenotype o f TM-31 cells, and the farnesyltransferase inhibitor may be potentially imp ortant as a novel antiproliferative therapy for NF1-derived astrocytomas.