Melanoma growth-stimulatory activity/GRO decreases collagen expression by human fibroblasts. Regulation by C-X-C but not C-C cytokines

• Published in: The Journal of biological chemistry 1993-01, Vol.268 (2), p.1338-1342
• Main Authors: UNEMORI, E. N, AMENTO, E. P, BAUER, E. A, HORUK, R
• Format: Article
• Language: English
• Subjects: Arthritis, Rheumatoid - metabolism; Base Sequence; Biological and medical sciences; Blotting, Northern; Cell Division - drug effects; Cell physiology; Cells, Cultured; Chemokine CXCL1; Chemokines, CXC; Chemotactic Factors - metabolism; Chemotactic Factors - pharmacology; Collagen - biosynthesis; Collagen - genetics; Cytokines - genetics; Cytokines - pharmacology; Fibroblasts - drug effects; Fibroblasts - metabolism; Fibroblasts - pathology; Fundamental and applied biological sciences. Psychology; Growth Substances - metabolism; Growth Substances - pharmacology; Humans; Intercellular Signaling Peptides and Proteins; Interleukin-8 - metabolism; Kinetics; Melanoma; Molecular and cellular biology; Multigene Family; Responses to growth factors, tumor promotors, other factors; Synovial Membrane - drug effects; Synovial Membrane - metabolism; Synovial Membrane - pathology; Transcription, Genetic - drug effects; Tumor Cells, Cultured
• ISSN: 0021-9258; 1083-351X
• DOI: 10.1016/S0021-9258(18)54080-1

Melanoma growth-stimulatory activity (MGSA)/GRO is well characterized as a potent neutrophil chemoattractant. In the present study, we have demonstrated that MGSA induced a dose-dependent decrease in the expression of interstitial collagens by rheumatoid synovial fibroblasts. The decrease was observed over a dose range of 0.6-6.0 nM MGSA. This effect was specific, as MGSA had no demonstrable effect on the expression of collagen-degrading metalloproteinases, nor did it affect the collagenase inhibitor, tissue inhibitor of metalloproteinases. It also had no effect on the proliferation rate of these fibroblasts, unlike its mitogenic effect on melanoma cells. The ability to inhibit collagen expression was also demonstrated by another member of the C-X-C branch of the platelet factor 4 superfamily, interleukin-8 (IL-8), but not by RANTES, MIP-1 alpha, or MIP-1 beta, which belong to the C-C branch. Steady-state levels of expression of MGSA and IL-8 transcripts in normal adult tissues were dissimilar, suggesting that expression may be an important level at which the activity of these cytokines is regulated. Direct binding experiments with 125I-MGSA on synovial fibroblasts have allowed us to identify an MGSA receptor with a KD of 10.1 nM and approximately 75,000 binding sites/fibroblast. 125I-MGSA binding was specific and could not be displaced by unlabeled IL-8. These results suggest that MGSA, as well as IL-8, may play a role other than that of neutrophil chemo-attractant and more specifically, may be important in the regulation of collagen turnover.