Isolation and characterization of transforming growth factors from human malignant gliomas: possible role of transforming growth factors in the pathogenesis of the gliosarcoma
This study provides the first direct experimental evidence that human malignant gliomas secrete soluble polypeptides with TGF-like activity. The conditioned medium from three well-characterized malignant glioma cell lines promote the growth of NRK indicator cells in soft agar. Following acid extraction and gel filtration, TGF-like activity was recovered from all three cell lines. Active fractions from gel filtration in two of the glioma cell lines (U-343 MG-A and SF-210) were further purified by reverse-phase HPLC. The TGF isolated from U-343 MG-A by HPLC is an acid- and heat-stable protein complex whose activity is destroyed by reducing agents and incubation with monospecific anti-TGF-alpha monoclonal antibodies. The NRK colony stimulating activity of this TGF is potentiated by the addition of TGF-beta. The partially purified U-343 MG-A TGF competes with radiolabeled (/sup 125/I)-ECF for the EGF-receptor on A431 epidermoid carcinoma cells. Finally, a total RNA preparation from U-343- MG-A contains a 4.8 kilobase mRNA for TGF-alpha. Therefore, U-343 MG-A secretes a soluble polypeptide with TGF-alpha-like activity. In contrast, the purified SF-210 malignant glioma cell line secretes an acid- and heat-stable TGF with neither TGF-alpha- nor TGF-beta-like activity.
- Research Organization:
- California Univ., San Francisco (USA)
- OSTI ID:
- 6945395
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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