T-kininogen inhibits fibroblast proliferation in the G(1) phase of the cell cycle.
By using synthetic protease inhibitors, several investigators have demonstrated that cysteine proteinases are required for cell proliferation. Kininogens are potent and specific physiological inhibitors of cysteine proteinases. We have used several mouse fibroblast-derived cell lines that express biologically active T-kininogen under the control of the mouse metallothionein promoter to test its effect on cell proliferation. Our results indicate that expression of T-kininogen results in diminished proliferative capacity, as measured by reduced cell numbers, both in logarithmically growing cultures and in G(0) cells induced to proliferate in response to serum. Furthermore, both fluorescence-activated cell sorting (FACS) analysis and incorporation of radioactive precursors into DNA suggest that the cells are unable to progress from G(0) through the S phase of the cell cycle in response to serum stimulation. However, we find that T-kininogen-expressing cell lines are still capable of responding to growth factors present in the serum, both by activating the ERK pathway and by expressing early genes, such as c-Fos and c-Jun. Thus, our results suggest that inhibition of cysteine proteinases by T-kininogen leads to inhibition of cell proliferation between the G(1) and S phases of the cell cycle.
Torres
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C
MCP-Hahnemann University, 2900 Queen Lane, Philadelphia, Pennsylvania 19129, USA.
Li
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M
Walter
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R
Sierra
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F
D016475:3T3 Cells; D000818:Animals; D015153:Blotting, Western; D002453:Cell Cycle; D002455:Cell Division; D002460:Cell Line; D002469:Cell Separation; D002478:Cells, Cultured; D019925:Cyclin A / Q000378:metabolism; D056743:Cyclin D3; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases / Q000378:metabolism; D016213:Cyclins / Q000378:metabolism; D003546:Cysteine Endopeptidases / Q000378:metabolism; D018076:DNA, Complementary / Q000378:metabolism; D005347:Fibroblasts / Q000378:metabolism*; D005434:Flow Cytometry; D016193:G1 Phase; D015723:Gene Library; D007704:Kininogens / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D051379:Mice; D008807:Mice, Inbred BALB C; D008840:Microfilament Proteins / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009124:Muscle Proteins; D010957:Plasmids / Q000378:metabolism; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
C534697:Ccnd3 protein, mouse; D019925:Cyclin A; D056743:Cyclin D3; D016213:Cyclins; D018076:DNA, Complementary; D007704:Kininogens; D008840:Microfilament Proteins; D009124:Muscle Proteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; C058992:Tagln protein, mouse; C495902:Cdk4 protein, mouse; D051358:Cyclin-Dependent Kinase 4; D018844:Cyclin-Dependent Kinases; D020928:Mitogen-Activated Protein Kinases; D003546:Cysteine Endopeptidases