Open AccessInsulin-like synergistic stimulation of DNA synthesis in Swiss 3T3 cells by the BSC-1 cell-derived growth inhibitor related to transforming growth factor type beta.
Author(s) -
Kenneth D. Brown,
Robert W. Holley
Publication year - 1987
Publication title -
proceedings of the national academy of sciences of the united states of america
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.011
H-Index - 771
eISSN - 1091-6490
pISSN - 0027-8424
DOI - 10.1073/pnas.84.11.3743
Subject(s) - bombesin , dna synthesis , growth factor , epidermal growth factor , endocrinology , medicine , transforming growth factor , stimulation , 3t3 cells , insulin , biology , receptor , transforming growth factor beta , cell growth , cell culture , chemistry , biochemistry , dna , neuropeptide , transfection , genetics
A cell growth inhibitor (GI), purified from BSC-1 cell-conditioned medium, has little if any effect on DNA synthesis when added alone to monolayer cultures of quiescent Swiss mouse 3T3 cells in serum-free medium. However, the inhibitor, which is closely related to transforming growth factor type beta (TGF-beta), exhibits a pronounced synergistic stimulation of DNA synthesis in combination with certain peptide (bombesin, vasopressin) or polypeptide (platelet-derived growth factor) mitogens. A similar synergistic response has been demonstrated for TGF-beta purified from human platelets. In the presence of 3 nM bombesin, a half-maximal stimulation of DNA synthesis was obtained at a GI concentration of approximately 60 pg/ml, with a maximal response at approximately 600 pg/ml. The synergistic interactions demonstrated by GI or TGF-beta in stimulating Swiss 3T3 cells closely resemble those previously shown for insulin, and we have observed that GI does not synergize with insulin to stimulate DNA synthesis in these cells. Like insulin, and in contrast to bombesin, vasopressin, and platelet-derived growth factor, GI does not activate cellular inositolphospholipid hydrolysis, calcium mobilization, or cross-regulation of epidermal growth factor receptor affinity. These results raise the possibility that the biochemical pathways activated by GI/TGF-beta and insulin converge at a post-receptor stage.