Induction and regulation of mRNA encoding 26-kDa protein in human cell lines treated with recombinant human tumor necrosis factor.

Abstract

A 26-kDa protein, originally described in human fibroblasts superinduced for interferon f3 (IFN-13) production, and termed IFN-f32 by other investigators, is induced by cycloheximide and by a 22-kDa, interleukin 1 (IL-1)-related factor. Although the structure and sequence of the corresponding gene show nonhomology with the IFN-f3 gene, the gene is identical to that of B-cell stimulatory factor 2, a human interleukin, and displays a very potent growth and differentiation factor activity for B lymphocytes. In this work we show that IL-1,8 and tumor necrosis factor (TNF) strongly induce the 26-kDa protein in FS-4 fibroblasts and in some transformed cell lines. Addition of cycloheximide to recombinant (r)IL-l and rTNF further enhances the level of 26-kDaprotein mRNA. We determined the kinetics of induction and the amounts of rTNF and rIL-1j3 required for optimal induction of this mRNA in FS-4 cells and in HeLa H21 cells and found that rIL-1f3 is a more efficient inducer of 26-kDa protein mRNA than is TNF. By analyzing the inducibility of the 26-kDa protein gene by rTNF and rIL-1/3 in a series of transformed cell lines that differ in their sensitivity to the cytotoxic action of TNF, we report a direct correlation between the 26-kDa protein mRNA expression and the resistance of these cells to the cytotoxic effect of TNF.When human fibroblast cells are induced to produce interferon (IFN)-p by treatment with poly(I)-poly(C) in the presence of cycloheximide (CHX), synthesis of a protein of 26 kDa (1), earlier described as , is stimulated.Induced epithelial cells (3) and peripheral blood lymphocytes (4) also express the 26-kDa-protein mRNA. Further, the gene coding for the 26-kDa protein is also induced by a highly purified interleukin 1ip (IL-1p3)-related protein obtained from con A-stimulated human leukocytes (5), later demonstrated to be identical to . Although it has been claimed that the 26-kDa protein has a weak IFN-like activity-neutralized by anti-IFN-p8 sera-the biological function of this molecule remained mysterious until the recent report of an identical cDNA sequence coding for an interleukin, active on Blymphocytes (7)(8)(9), and having a potent growth factor activity on the same cells (10).Tumor necrosis factor (TNF) is a cytokine secreted by macrophages and/or monocytic cell lines upon stimulatione.g., by lipopolysaccharide (LPS). It was discovered originally in the sera of mice treated with bacillus CalmetteGuerin (BCG), followed by an endotoxin challenge for a few hours, a substance that causes hemorrhagic necrosis, or, in some cases, complete regression of certain transplanted tumors in mice (11). In the last few years human TNF cDNA has been cloned, sequenced, and efficiently expressed in Escherichia coli by several groups (12)(13)(14). The biological activities exerted by TNF are very broad. In vitro recombinant (r)TNF has divergent effects on the cell physiology, being either cytocidal and cytostatic on some transformed cell lines and inactive on others (15), or growth-promoting in normal dip...

Tumor necrosis factor Characterization at the molecular, cellular and in vivo level

“…One of the better studied proteins induced in many cell types by TNF is IL6. There is no correlation between sensitivity of the cell to the cytotoxic action of TNF and the inducibility of the IL6 gene; the IL6 gene can readily be induced not only in normal diploid fibroblasts, but also in TNF-resistant tumor cell lines, such as MG63 [141]. On the other hand, the IL6 gene cannot be induced in the very sensitive WEHI or in the human transformed cell lines BT20 or MCF7.…”

Tumor necrosis factor and immune interferon synergistically induce cytochrome b-245 heavy-chain gene expression and nicotinamide-adenine dinucleotide phosphate hydrogenase oxidase in human leukemic myeloid cells.

“…The kinetics ofexpression ofNADPH oxidase activity and respiratory burst capability (as evaluated by measurement of H202 release in response to TPA) approximated that of cytochrome b-245 appearance, but were somehow delayed compared to the appearance of X-CGD transcripts. One possibility that could explain these data is the existence of other limiting cofactors, such as the flavoprotein or the cytosolic cofactor activity, whose expression has been shown to be affected by differentiation inducers (22,47 (50,51) and HeLa (52) cells, and induced expression of c-fos, c-myc (53), and IFN-/32 (54,55) in fibroblasts, do not require de novo protein synthesis. Enhancement of class I MHC gene expression by TNF was reported to be prevented by cycloheximide, but those results are difficult to interpret because no control of constitutively expressed genes was reported ( 13).…”

Dexamethasone regulation of the expression of cytokine mRNAs induced by interleukin‐1 in the astrocytoma cell line U373MG

“…Its biological activities include induction of various cytokines. IL-1 has been shown to induce the production of granulocytemacrophage colony-stimulating factor [5][6][7][8][9][10][11][12][13], granulocyte CSF (G-CSF) [9][10][11][12] and B-cell stimulatory factor-2/interleukin-6/interferon-fl2 (IFN-~2)/26-kDa protein [14][15][16][17]. Recently it has also been reported that IL-1 can induce its own synthesis [18][19][20].…”