TM-1 cells from an established human malignant glioma cell line produce PDGF, TGF-alpha, and TGF-beta which cooperatively play a stimulatory role for an autocrine growth promotion.
We have previously established a human malignant glioma cell line, TM-1. TM-1 cells could proliferate in the serum-free medium. In the present study, immunochemical analysis demonstrated that platelet-derived growth factor (PDGF), transforming growth factor (TGF)-alpha, and TGF-beta are present in the serum-free medium conditioned by growing TM-1 cells. While the cells appeared to possess a single type of binding sites for epidermal growth factor (EGF) with properties comparable to those determined for other tumor cells, the conditioned medium did not contain EGF.PDGF, TGF-alpha, and EGF added exogenously to serum-free media stimulated thymidine incorporation into DNA of TM-1 cells. In addition, antibodies specific for PDGF and TGF-alpha suppressed this activity. These results indicate autocrine and stimulatory roles of PDGF and TGF-alpha for the proliferation of TM-1 cells. As observed for other tumor cells, TGF-beta by itself weakly suppressed thymidine incorporation by TM-1 cells. However, TGF-beta employed in combination with TGF-alpha or EGF appeared to stimulate thymidine incorporation, suggesting that a cooperative action of TGF-beta with different growth factors may be involved in the stimulatory growth regulation at least for TM-1 cells.
Kurimoto
M
M
Department of Neurosurgery, Toyama Medical and Pharmaceutical University, Faculty of Medicine, Japan.
Endo
S
S
Arai
K
K
Horie
Y
Y
Nogami
K
K
Takaku
A
A
D002455:Cell Division; D004247:DNA / Q000096:biosynthesis; D066246:ErbB Receptors / Q000378:metabolism; D005910:Glioma / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D010982:Platelet-Derived Growth Factor / Q000378:metabolism*; D016211:Transforming Growth Factor alpha / Q000378:metabolism*; D016212:Transforming Growth Factor beta / Q000378:metabolism*; D014407:Tumor Cells, Cultured
D010982:Platelet-Derived Growth Factor; D016211:Transforming Growth Factor alpha; D016212:Transforming Growth Factor beta; D004247:DNA; D066246:ErbB Receptors