Basic fibroblast growth factor-like activity and receptors are expressed in a human glioma cell line

Basic fibroblast growth factor (bFGF), a potent mitogen and angiogenic peptide, has been examined as an autocrine regulator of glioma cell growth. The addition of purified bovine pituitary bFGF to an established human glioma cell line, SNB-19, doubled the density of these cells in chemically defined medium. Half-maximal stimulation occurred at 8.2 ng/ml (480 pM). Also, human recombinant bFGF (hr-bFGF) significantly enhanced the growth of SNB-19 cells in soft agar. SNB-19 cells expressed both high and low affinity binding sites for hr-bFGF. These cells expressed approximately 13,000 high affinity sites/cell (Kd = 16.6 +/- 1.7 pM) and 9.5 x 10(6) low affinity sites/cell (Kd = 61.2 +/- 4.1 nM). The results of cross-linking experiments with iodinated hr-bFGF demonstrated the presence of two bands with molecular masses of 145 and 130 kDa. High affinity receptors were also demonstrated in SNB-19 tumors grown in nude mice. SNB-19 cell extracts contained mitogenic activity that eluted from heparin-agarose with high salt (1.2-2 M NaCl) and exhibited many properties normally associated with authentic bFGF. This material cross-reacted with a monoclonal antibody to hr-bFGF, comigrated with hr-bFGF by Western blot analysis, competed with 125I-hr-bFGF in a radioreceptor assay, and stimulated SNB-19 cell growth. These results indicate that a human glioma cell line both expresses and utilizes a bFGF-like growth factor. Such a factor may be an important autocrine regulator of glioma cell growth and may also facilitate its neoplastic progression.