scholarly journals Role of arachidonic acid metabolism in transcriptional induction of tumor necrosis factor gene expression by phorbol ester.

1989 ◽  
Vol 9 (1) ◽  
pp. 252-258 ◽  
Author(s):  
J Horiguchi ◽  
D Spriggs ◽  
K Imamura ◽  
R Stone ◽  
R Luebbers ◽  
...  

The treatment of human HL-60 promyelocytic leukemia cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) is associated with induction of tumor necrosis factor (TNF) transcript. The study reported here has examined TPA-induced signaling mechanisms responsible for the regulation of TNF gene expression in these cells. Run-on assays demonstrated that TPA increases TNF mRNA levels by transcriptional activation of this gene. The induction of TNF transcripts by TPA was inhibited by the isoquinolinesulfonamide derivative H7 but not by HA1004, suggesting that this effect of TPA is mediated by activation of protein kinase C. TPA treatment also resulted in increased arachidonic acid release. Moreover, inhibitors of phospholipase A2 blocked both the increase in arachidonic acid release and the induction of TNF transcripts. These findings suggest that TPA induces TNF gene expression through the formation of arachidonic acid metabolites. Although indomethacin had no detectable effect on this induction of TNF transcripts, ketoconazole, an inhibitor of 5-lipoxygenase, blocked TPA-induced increases in TNF mRNA levels. Moreover, TNF mRNA levels were increased by the 5-lipoxygenase metabolite leukotriene B4. In contrast, the cyclooxygenase metabolite prostaglandin E2 inhibited the induction of TNF transcripts by TPA. Taken together, these results suggest that TPA induces TNF gene expression through the arachidonic acid cascade and that the level of TNF transcripts is regulated by metabolites of the pathway, leukotriene B4 and prostaglandin E2.

1989 ◽  
Vol 9 (1) ◽  
pp. 252-258
Author(s):  
J Horiguchi ◽  
D Spriggs ◽  
K Imamura ◽  
R Stone ◽  
R Luebbers ◽  
...  

The treatment of human HL-60 promyelocytic leukemia cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) is associated with induction of tumor necrosis factor (TNF) transcript. The study reported here has examined TPA-induced signaling mechanisms responsible for the regulation of TNF gene expression in these cells. Run-on assays demonstrated that TPA increases TNF mRNA levels by transcriptional activation of this gene. The induction of TNF transcripts by TPA was inhibited by the isoquinolinesulfonamide derivative H7 but not by HA1004, suggesting that this effect of TPA is mediated by activation of protein kinase C. TPA treatment also resulted in increased arachidonic acid release. Moreover, inhibitors of phospholipase A2 blocked both the increase in arachidonic acid release and the induction of TNF transcripts. These findings suggest that TPA induces TNF gene expression through the formation of arachidonic acid metabolites. Although indomethacin had no detectable effect on this induction of TNF transcripts, ketoconazole, an inhibitor of 5-lipoxygenase, blocked TPA-induced increases in TNF mRNA levels. Moreover, TNF mRNA levels were increased by the 5-lipoxygenase metabolite leukotriene B4. In contrast, the cyclooxygenase metabolite prostaglandin E2 inhibited the induction of TNF transcripts by TPA. Taken together, these results suggest that TPA induces TNF gene expression through the arachidonic acid cascade and that the level of TNF transcripts is regulated by metabolites of the pathway, leukotriene B4 and prostaglandin E2.


2002 ◽  
Vol 277 (42) ◽  
pp. 39499-39506 ◽  
Author(s):  
Lasse Foghsgaard ◽  
Ulrik Lademann ◽  
Dorte Wissing ◽  
Birgit Poulsen ◽  
Marja Jäättelä

Endocrinology ◽  
1997 ◽  
Vol 138 (3) ◽  
pp. 1078-1084 ◽  
Author(s):  
Jean-Paul Thissen ◽  
Josiane Verniers

Abstract The cytokines are the putative mediators of the catabolic reaction that accompanies infection and trauma. Evidence suggests that their catabolic actions are indirect and potentially mediated through changes in hormonal axis such as the hypothalamo-pituitary-adrenal axis. Insulin-like growth factor I (IGF-I) is a GH-dependent growth factor that regulates the protein metabolism. To determine whether cytokines can directly inhibit the production of IGF-I by the liver, we investigated the regulation of IGF-I gene expression by interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α (10 ng/ml) in a model of rat primary cultured hepatocytes. Hepatocytes were isolated by liver collagenase perfusion and cultured on Matrigel 48 h before experiments. Each experiment was performed in at least three different animals. In the absence of GH, IL-1β and TNF-α did not affect the IGF-I messenger RNA (mRNA) basal levels, whereas IL-6 increased it by a factor of 2.5 after 24 h (P < 0.05). GH (500 ng/ml) alone stimulated the IGF-I gene expression markedly (5- to 10-fold increase) after 24 h (P < 0.001). IL-1β, and TNF-α to a lesser extent, dramatically inhibited the IGF-I mRNA response to GH (IL-1β: −82%, P < 0.001 and TNF-α: −47%, P < 0.01). The half-maximal inhibition of the IGF-I mRNA response to GH was observed for a concentration of IL-1β between 0.1 and 1 ng/ml. Moreover, IL-1β abolished the IL-6-induced IGF-I mRNA response. In contrast, IL-6 did not impair the IGF-I mRNA response to GH. To determine the potential role of the GH receptor (GHR) and the GH-binding protein (GHBP) in this GH resistance, we assessed the GHR and GHBP mRNAs response to these cytokines. GH alone did not affect the GHR/GHBP mRNA levels. IL-1β markedly decreased the GHR and GHBP mRNA levels (respectively, −68% and −60%, P < 0.05). Neither TNF-α nor IL-6 affected the GHR/GHBP gene expression. In conclusion, our results show that IL-1β, and TNF-α to a lesser extent, blunt the IGF-I mRNA response to GH. The resistance to GH induced by IL-1β might be mediated by a decrease of GH receptors, as suggested by the marked reduction of GHR mRNA. These findings suggest that decreased circulating IGF-I, in response to infection and trauma, may be caused by a direct effect of cytokines at the hepatocyte level.


Blood ◽  
1990 ◽  
Vol 75 (4) ◽  
pp. 958-962
Author(s):  
AP Sappino ◽  
W Seelentag ◽  
MF Pelte ◽  
P Alberto ◽  
P Vassalli

We investigated the mRNA content for tumor necrosis factor (TNF)/cachectin and lymphotoxin (LT) in tumoral tissues of a prospective series of 35 non-Hodgkin's (NHL) and 23 Hodgkin's (HL) lymphomas, to assess their postulated contribution to systemic symptoms. Total RNAs were extracted from diagnostic tissue specimens and submitted to Northern blot analysis, using specific TNF and LT cRNA probes. High amounts of TNF mRNA were found exclusively in NHL (12/35). The majority (9/12) of these were low grade B-cell NHL, which contained a uniform population of malignant cells. In contrast, abundant LT mRNA production was detected in most HL (21/23) and in 19 of 35 NHL. The highest LT mRNA levels were observed in high grade NHL and in lymphocytic predominant subtypes of HL specimens. A significant correlation was found between TNF/cachectin and LT gene expression in NHL and the presence of constitutional symptoms. The biologic and prognostic implications of these preliminary findings are presently unknown, but they demonstrate that lymphoma tissues sharing common histologic features are highly heterogeneous in their ability to synthesize cytokines susceptible to playing a role in the growth control of malignant cells. These results suggest that the evaluation of TNF/cachectin and LT production in lymphomas may help to elucidate the mechanisms of tumoral fever and cachexia.


Blood ◽  
1990 ◽  
Vol 75 (4) ◽  
pp. 958-962 ◽  
Author(s):  
AP Sappino ◽  
W Seelentag ◽  
MF Pelte ◽  
P Alberto ◽  
P Vassalli

Abstract We investigated the mRNA content for tumor necrosis factor (TNF)/cachectin and lymphotoxin (LT) in tumoral tissues of a prospective series of 35 non-Hodgkin's (NHL) and 23 Hodgkin's (HL) lymphomas, to assess their postulated contribution to systemic symptoms. Total RNAs were extracted from diagnostic tissue specimens and submitted to Northern blot analysis, using specific TNF and LT cRNA probes. High amounts of TNF mRNA were found exclusively in NHL (12/35). The majority (9/12) of these were low grade B-cell NHL, which contained a uniform population of malignant cells. In contrast, abundant LT mRNA production was detected in most HL (21/23) and in 19 of 35 NHL. The highest LT mRNA levels were observed in high grade NHL and in lymphocytic predominant subtypes of HL specimens. A significant correlation was found between TNF/cachectin and LT gene expression in NHL and the presence of constitutional symptoms. The biologic and prognostic implications of these preliminary findings are presently unknown, but they demonstrate that lymphoma tissues sharing common histologic features are highly heterogeneous in their ability to synthesize cytokines susceptible to playing a role in the growth control of malignant cells. These results suggest that the evaluation of TNF/cachectin and LT production in lymphomas may help to elucidate the mechanisms of tumoral fever and cachexia.


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