Tumor necrosis factor receptor-associated factor 1 gene overexpression in B-cell chronic lymphocytic leukemia: analysis of NF-κB/Rel–regulated inhibitors of apoptosis

Blood ◽  
2002 ◽  
Vol 100 (10) ◽  
pp. 3749-3756 ◽  
Author(s):  
Gerd Munzert ◽  
Dieter Kirchner ◽  
Heike Stobbe ◽  
Lothar Bergmann ◽  
Roland M. Schmid ◽  
...  

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by a resistance toward apoptosis-inducing agents. Nuclear factor-κB (NF-κB)/Rel has been shown to regulate the expression of antiapoptotic genes, such as members of the inhibitor of apoptosis protein (IAP) and tumor necrosis factor receptor-associated factor (TRAF) gene families. Expression and regulation of NF-κB/Rel–dependent inhibitors of apoptosis have not been collectively studied in B-CLL. We examined expression of known NF-κB/Rel–regulated antiapoptotic genes by RNAse protection assay, real-time polymerase chain reaction, and immunoblotting in patients with B-CLL. TRAF1 and to a lesser extent TRAF2 were overexpressed in B-CLL lymphocytes as compared with normal CD19+ B cells. TRAF1 overexpression did not correlate with markers of disease progression or overall survival. Furthermore, we found high constitutive expression of the IAP genes c-IAP-1, c-IAP-2, and XIAP both in normal and B-CLL lymphocytes. Focusing on the regulation of TRAF1, NF-κB/Rel activity in B-CLL nuclear extracts was shown to bind to TRAF1 promoter elements. However, IκB kinase (IKK) activity was not increased in CLL lymphocytes as compared with normal CD19+ B cells. The known IKK inhibitor sulfasalazine did not compromise TRAF1 expression. Thus, although our study revealed a common expression pattern of NF-κB/Rel–regulated inhibitors of apoptosis, our findings indicate an IKK-independent regulation of TRAF1 in B-CLL.

Blood ◽  
1990 ◽  
Vol 76 (2) ◽  
pp. 393-400 ◽  
Author(s):  
R Foa ◽  
M Massaia ◽  
S Cardona ◽  
AG Tos ◽  
A Bianchi ◽  
...  

Abstract Tumor necrosis factor-alpha (TNF) is a cytokine that displays a pleomorphic array of effects on different cell populations. Evidence is presented that TNF may be constitutively produced by B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia (HCL) cells and that it may play a relevant role in these diseases. These conclusions are based on the presence of circulating levels of TNF in the serum of 20 of the 24 patients tested (83.3%), while undetectable values were found in normal sera. The suggestion that the increased serum levels were due to the leukemic cell population is strengthened by the evidence that purified B-CLL and HCL cells may constitutively release variable degrees of TNF. These levels markedly increase after incubation with interferon gamma or phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). The cellular release of TNF by primary B-CLL cells was significantly (P less than .001) higher in B-CLL stage O-I patients compared with stage II-III patients. The demonstration that, in B-cell chronic lymphoproliferative disorders, the pathologic cells may release TNF was further confirmed by the presence of the mRNA for this cytokine in primary and/or in pre-activated cells. Recombinant TNF was capable of inducing a proliferative signal only in a minority of cases (4/24); in most cases it was ineffective, and, in a few, it reduced the degree of proliferation. Furthermore, in costimulatory experiments with interleukin-2 and PHA plus PMA, TNF was ineffective. On the other hand, when primary B-CLL cells were incubated in the presence of an anti-TNF antibody, in 8 of 12 independent experiments a 2- to 15-fold increase in thymidine uptake was documented. Taken together, these results suggest that TNF may play a regulatory role in the progression of the neoplastic clone in B-cell chronic lymphoproliferative disorders and may be implicated in some of the side effects associated with these diseases.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 4149-4149
Author(s):  
Claudia Duerr ◽  
Angela Schulz ◽  
Sibylle Ohl ◽  
Thorsten Zenz ◽  
Stephan Stilgenbauer ◽  
...  

Abstract B-cell Chronic Lymphocytic Leukemia (CLL) represents the most common leukemia among adults in the western world and remains still incurable. CLL is characterized by the accumulation of malignant B-cells in the peripheral blood and the lymphoid organs due to apoptosis resistance. Removing the cells from their physiological microenvironment spontaneously drives them into apoptosis in vitro unless they are supported by bystander cells (e.g. stromal cells or accessory leukocytes) or soluble factors such as cytokines produced by these cells. In order to identify differences in the biology of healthy B-cells and the leukemic clones we performed comparative microarray analyses of both cell types before and after cultivation in high cell density that allows cell-cell interactions of CLL cells with accessory leukocytes. These studies revealed the establishment of an inflammatory microenvironment in CLL characterized by the transcriptional upregulation of several cytokines. Antibody array analyses of culture supernatants and blood serum samples confirmed the upregulation of these proteins and their relevance for CLL. The 11 most deregulated cytokines were quantified in the serum of 250 CLL patients of the German CLL8 study cohort and 50 age- and sex-matched controls in order to identify novel predictive or prognostic markers. Bioinformatical analyses of the data are currently ongoing. Among other proteins, we found Tumor Necrosis Factor Receptor Type 1 (TNFR-1) to be significantly upregulated in the malignant B-cells under survival-maintaining cultivation as well as in CLL serum, but not in healthy controls (Figure 1). To exploit the difference in TNFR-1 biology, we treated CLL cells with TNF-α in combination with wogonin which is known to block the survival supporting pathway propagated by TNFR-1 upon TNF-α binding. This combinational treatment strategy effectively triggered Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
1990 ◽  
Vol 76 (2) ◽  
pp. 393-400 ◽  
Author(s):  
R Foa ◽  
M Massaia ◽  
S Cardona ◽  
AG Tos ◽  
A Bianchi ◽  
...  

Tumor necrosis factor-alpha (TNF) is a cytokine that displays a pleomorphic array of effects on different cell populations. Evidence is presented that TNF may be constitutively produced by B-cell chronic lymphocytic leukemia (B-CLL) and hairy cell leukemia (HCL) cells and that it may play a relevant role in these diseases. These conclusions are based on the presence of circulating levels of TNF in the serum of 20 of the 24 patients tested (83.3%), while undetectable values were found in normal sera. The suggestion that the increased serum levels were due to the leukemic cell population is strengthened by the evidence that purified B-CLL and HCL cells may constitutively release variable degrees of TNF. These levels markedly increase after incubation with interferon gamma or phytohemagglutinin (PHA) plus phorbol myristate acetate (PMA). The cellular release of TNF by primary B-CLL cells was significantly (P less than .001) higher in B-CLL stage O-I patients compared with stage II-III patients. The demonstration that, in B-cell chronic lymphoproliferative disorders, the pathologic cells may release TNF was further confirmed by the presence of the mRNA for this cytokine in primary and/or in pre-activated cells. Recombinant TNF was capable of inducing a proliferative signal only in a minority of cases (4/24); in most cases it was ineffective, and, in a few, it reduced the degree of proliferation. Furthermore, in costimulatory experiments with interleukin-2 and PHA plus PMA, TNF was ineffective. On the other hand, when primary B-CLL cells were incubated in the presence of an anti-TNF antibody, in 8 of 12 independent experiments a 2- to 15-fold increase in thymidine uptake was documented. Taken together, these results suggest that TNF may play a regulatory role in the progression of the neoplastic clone in B-cell chronic lymphoproliferative disorders and may be implicated in some of the side effects associated with these diseases.


Blood ◽  
1989 ◽  
Vol 73 (5) ◽  
pp. 1242-1246 ◽  
Author(s):  
W Digel ◽  
M Stefanic ◽  
W Schoniger ◽  
C Buck ◽  
A Raghavachar ◽  
...  

Abstract The biologic effects of recombinant tumor necrosis factor-alpha (rTNF- alpha) and the expression of specific TNF membrane receptors on isolated neoplastic B cells from previously untreated patients with chronic lymphocytic leukemia (CLL) were investigated in vitro. Isolated B cells were incubated up to six days with various concentrations of rTNF-alpha (0.1 to 100 ng/mL). B cells from most patients proliferated ranged from two to 104 times that of unstimulated cells from the same patients. An optimal proliferative effect was achieved at 25 ng/mL rTNF- alpha and an incubation time between 96 and 120 hours, whereas a low concentration of rTNF-alpha (1 ng/mL) reduced [3H]TdR incorporation in four cases. Metaphase cells were detected in the rTNF-alpha-stimulated cultures that proliferated in response to rTNF-alpha. B cells from three of ten patients proliferated spontaneously and proliferation was further enhanced in two patients by rTNF-alpha. TNF binding assays gave a value of approximately 390 to 1,400 binding sites/cell for TNF and a dissociation constant (kd) of approximately 60 pmol/L. These data indicate that rTNF-alpha, in contrast to its cytotoxic/cytostatic effects, can also induce proliferation of tumor cells.


Sign in / Sign up

Export Citation Format

Share Document