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Differential inhibitory effects of TGF‐β on EGF‐, PDGF‐, and HBGF‐1‐stimulated MG63 human osteosarcoma cell growth: Possible involvement of growth factor interactions at the receptor and postreceptor levels
Author(s) -
Mioh Hiroyuki,
Chen JanKan
Publication year - 1989
Publication title -
journal of cellular physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.529
H-Index - 174
eISSN - 1097-4652
pISSN - 0021-9541
DOI - 10.1002/jcp.1041390309
Subject(s) - platelet derived growth factor receptor , epidermal growth factor , growth factor , platelet derived growth factor , transforming growth factor , tyrosine kinase , receptor , biology , tyrosine phosphorylation , endocrinology , medicine , microbiology and biotechnology , cancer research , biochemistry
The growth of MG63 human osteosarcoma cell line in 5% serum is stimulated by epidermal growth factor (EGF), platelet‐derived growth factor (PDGF), or heparin‐binding growth factor‐1 (HBGF‐1). The mitogenic effect of EGF and PDGF is completely blocked by TFG‐β at 1 ng per ml and the effect of HBGF‐1 is attenuated by 75–80%. Treatment of MG63 cells with TGF‐β reduces HBGF‐1 receptor binding affinity from 1.24 × 10–11 M to 3.51 × 10–11 M with no change on the receptor number (1.1. × 103 per cell). The receptor‐binding affinity of EGF and PDGF is not altered by TGF‐β treatment; however, the number of EGF receptor is increased by 25%. Both EGF and PDGF stimulate MG63 cellular tyrosine kinase activity, and such stimulation is inhibited by TGF‐β pretreatment. No change in the cellular protein tyrosine phosphorylation pattern can be detected in HBGF‐1‐stimulated cells with and without TGF‐β pretreatment. These data suggest that TGF‐β inhibits EGF and PDGF mitogenicity by blocking EGF‐ and PDGF‐stimulated tyrosine kinase activity and attenuates HBGF‐1 mitogenicity by decreasing its receptor affinity.