The angiogenic activity in the supernatants of cultured cells derived from human CNS tumors was examined by a bioassay method using chick chorioallantoic membrane (CAM). A quantitative assessment was designed to obtain a more accurate evaluation of angiogenesis on CAM.
Three out of five glioma cell lines, three out of four primary cultures of meningiomas and one metastatic tumor cell line showed angiogenic activity in the culture supernatants. The angiogenic activity was destroyed by ribonuclease or heating at 80°C for 30 minutes but remained intact with exposure to trypsin, deoxyribonuclease or heating at 56°C for 30 minutes. TAF samples obtained from glioma cells which had been irradiated (2, 500 R) before TAF extraction, also showed angiogenic activity.
TAF was present in the supernatants of long-term cultured human CNS tumor cell lines and primary cultures of meningiomas. Thus, the nature of TAF may related to RNA of the tumor cells and the TAF producing ability of these cells is apparently not inhibited by irradiation.