PHENOTYPIC CHARACTERIZATION OF THE HUMAN FIBROUS HISTIOCYTOMA GIANT-CELL TUMOR (GCT) CELL-LINE AND ITS CYTOKINE REPERTOIRE

The pleiotropic nature of malignant fibrous histiocytomas (MFH) is man ifested as mixed cellular infiltrates consisting of myofibroblasts, hi stiomonocytes, and neutrophils. We detail in this report the phenotypi c characteristics of the human fibrous histiocytoma giant cell tumor ( GCT) cell line that establish its mesenchymal origin. The latter is un derscored by the ability of GCT cells to express mRNA for transforming growth factor P (TGF-beta) as well as both A and B chains of platelet -derived growth factor (PDGF). GCT cells also support the binding of C D34(+) cells, but less efficiently than do normal marrow stromal cells . Since cytokines elaborated by MFH may mediate in part the recruitmen t of monocytes and neutrophils into tumor-infiltrated tissues, we have determined the cytokine repertoire of the GCT cell line, already know n for its ability to elaborate colony-stimulating factors (CSFs) and i nterleukin-1 (IL-1). GCT cells express IL-1 alpha, IL-1 beta, IL-6, ma crophage colony-stimulating factor (M-CSF or CSF-1), granulocyte-macro phage colony-stimulating factor (GM-CSF), granulocyte colony-stimulati ng factor (G-CSF), and IL-8. No detectable mRNA for IL-3, IL-4, IL-7, and tumor necrosis factor-alpha (TNF-alpha) was detected in GCT cells by polymerase chain reaction (PCR). Expression of cytokine mRNAs was r esponsive to agents such as dexamethasone (dex), 12-O-tetradecanoyl ph orbol 13-acetate (phorbol diester or TPA), and TNF-alpha. Thus, this c ell line provides a useful model for understanding the pathobiology of MFH and hematopoietic progenitor interactions with mesenchymal/stroma l cells.