scholarly journals HuR Affects Proliferation and Apoptosis of Chronic Lymphocytic Leukemia Cells via NF-κB Pathway

2020 ◽  
Vol 2020 ◽  
pp. 1-7
Author(s):  
Kai Xiao ◽  
Lin Yang ◽  
Xinfeng Gao ◽  
Ying An ◽  
Wei Xie ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Lymphocytes ◽  
Caspase 3 ◽  
Human Tumor ◽  
Lymphocytic Leukemia ◽  
Cell Counting ◽  
Cell Sensitivity ◽  
Proliferation And Apoptosis ◽  
Potential Strategy ◽  
The Relationship

Objective. To investigate the effects of HuR protein on the treatment of chronic lymphocytic leukemia (CLL). Methods. LCL lymphoblast cells and B lymphocytes were subjected to HuR overexpression (OV) or interference (IV). Western blot was used to observe the protein expression of human tumor necrosis factor-associated factor 1 (TRAF1), human inhibitor of nuclear factor kappa-B kinase α (IKK-α), NF-κB-inducing kinase (NIK), and p52. Flow cytometry was performed to evaluate apoptosis, and the mRNA expression of TRAF1 was examined by quantitative reverse transcription polymerase chain reaction. Immunofluorescence was carried out to visualize the expression of HuR, and the relationship between HuR and TRAF1 was observed by pull-down test. Cell sensitivity to chlorambucil (CLB) and fludarabine (Flu) was assessed by Cell Counting Kit-8. Results. The expression of HuR and TRAF1 in LCLs was significantly increased compared to that in B lymphocytes. Compared with the control, HuR OV significantly increased the expression of TRAF1 (P<0.05), whereas it was significantly decreased in the IV group (P<0.05). HuR can bind to TRAF1 directly, and the binding rate is positively correlated with HuR expression. After inhibiting HuR, the expression of TRAF1, IKK-α, NIK, p52, pro-Caspase 3, and PARP was significantly upregulated in LCLs and B lymphocytes (P<0.05), while Caspase 3 was downregulated (P<0.05). Compared with the control, the proliferation of LCLs and B lymphocytes treated by CLB and Flu decreased significantly after HuR blockade (P<0.05). Conclusion. HuR may be a key protein regulating CLL resistance. After inhibiting HuR, inflammatory response and apoptosis were significantly increased, and the cell sensitivity to CLB and Flu increased, suggesting that inhibiting HuR activity may be a potential strategy to solve the problem of drug resistance in CLL cells.

Modulation of the activity of calcium-activated neutral proteases (calpains) in chronic lymphocytic leukemia (B-CLL) cells

Blood ◽  
2002 ◽  
Vol 100 (5) ◽  
pp. 1802-1809 ◽  
Author(s):  
Jacek M. Witkowski ◽  
Emilia Zmuda-Trzebiatowska ◽  
Jakub M. Swiercz ◽  
Miroslawa Cichorek ◽  
Hanna Ciepluch ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Lymphocytes ◽  
Caspase 3 ◽  
Cell Types ◽  
Lymphocytic Leukemia ◽  
Calcium Dependent ◽  
Proliferative Control ◽  
Casein Zymography ◽  
Neutral Proteases

Decreased susceptibility to apoptosis and impaired proliferative control are thought to be responsible for prolonged life span and accumulation of chronic lymphocytic leukemia (B-CLL) cells. The activity of calpains (calcium-dependent, neutral proteases, active in the cells responding to signals inducing a rise of cytoplasmic Ca++) is involved in the regulation of apoptosis of some cell types by interaction with caspase-3. This work verifies the hypothesis of the abnormal activity of calpains and its role in reduced apoptosis of the B-CLL cells. Casein zymography, reverse transcriptase–polymerase chain reaction, and Western blotting were used for identification and quantification of the activity and expression of calpains in B-CLL cells and purified normal B lymphocytes. The activity and expression of μ-calpain (requiring micromolar Ca++ for activation) are significantly higher in the leukemic than in nonmalignant cells. Contrarily, the activity and expression of m-calpain (requiring millimolar Ca++) as well as the expression of calpastatin (an endogenous inhibitor of calpains) are unchanged or reduced in the B-CLL lymphocytes. Correspondingly, the activity of caspase-3 is many times lower in the B-CLL cells than in normal B lymphocytes. Inhibition of overexpressed μ-calpain in living B-CLL cells in vitro results in doubling of the proportion of the cells undergoing spontaneous apoptosis. This observation suggests a possible role for calpains in longer survival of the B-CLL cells and may open new therapeutic possibilities.

scholarly journals Functional heterogeneity of B-CLL lymphocytes: dissociated responsiveness to growth factors and distinct requirements for a first activation signal

Blood ◽  
1987 ◽  
Vol 70 (4) ◽  
pp. 1105-1110
Author(s):  
S Karray ◽  
H Merle-Beral ◽  
A Vazquez ◽  
JP Gerard ◽  
P Debre ◽  
...  
Keyword(s):  
Molecular Weight ◽  
Growth Factors ◽  
Growth Factor ◽  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
B Lymphocytes ◽  
Lymphocytic Leukemia ◽  
Functional Heterogeneity ◽  
B Cell Growth Factor ◽  
Directed Growth

We studied the effects of B cell directed growth factors on B lymphocytes from 11 patients with chronic lymphocytic leukemia (B-CLL). B-CLL lymphocytes were costimulated with anti-mu antibody (Ab) and with three growth factor preparations: recombinant IL2, B cell growth factor (BCGF) (20 kiloDalton (kD) BCGF) and a high molecular weight BCGF (50 kD BCGF). IL2 was the more active factor (in six of 11 patients). The effect of IL2 was dependent on a costimulation with anti-mu Ab or occurred independently of anti-mu Ab, according to the patients. This pattern of reactivity did not correlate with the presence or absence of the IL2 receptor (IL2-R) molecule on fresh B-CLL lymphocytes. Five patients responded to the 20 kD BCGF. Although four of them were also strong responders to IL2, one strongly responded to the 20 kD BCGF and did not respond to IL2. Only one patient responded to the 50 kD BCGF. When an anti-IL2-R Ab was introduced into the culture, only the responsiveness to IL2 was abolished: thus both 20 kD and 50 kD BCGFs activate B-CLL lymphocytes independently of the IL2-R. These results show that several B cell directed growth factors can act independently to support the proliferation of B-CLL lymphocytes.

scholarly journals Characterization of the phytohemagglutinin-induced proliferating lymphocyte subpopulations in chronic lymphocytic leukemia patients using a clonogenic agar technique and monoclonal antibodies

Blood ◽  
1981 ◽  
Vol 58 (5) ◽  
pp. 1053-1055 ◽  
Author(s):  
S Davis
Keyword(s):  
T Cells ◽  
Monoclonal Antibodies ◽  
Chronic Lymphocytic Leukemia ◽  
B Lymphocytes ◽  
Peripheral Blood Lymphocytes ◽  
Lymphocytic Leukemia ◽  
Helper T Cells ◽  
Suppressor T Lymphocytes ◽  
Pha Stimulation

Abstract Peripheral blood lymphocytes from normal donors and patients with chronic lymphocytic leukemia, B-cell type, were purified into T, helper T, and suppressor T lymphocytes by fluorescence-activated cell sorting using OKT3, OKT4, and OKT8 monoclonal antibodies. The maximum response of the purified subpopulations to stimulation by phytohemagglutinin (PHA) was determined by measuring the production of colonies when the stimulated cells were grown on agar. The helper T cells in normal and CLL patients were the most responsive to PHA stimulation, although the responsiveness of helper T cells to PHA was decreased in CLL. Purified CLL B cells responded minimally to PHA stimulation, but normal B lymphocytes did not. The abnormal response of CLL lymphocytes to PHA appears to be due abnormal helper T cells, and, to a smaller extent, to the ability of CLL B lymphocytes to respond.

Flavopiridol Induces Apoptosis in Chronic Lymphocytic Leukemia Cells Via Activation of Caspase-3 Without Evidence of bcl-2 Modulation or Dependence on Functional p53

Blood ◽  
1998 ◽  
Vol 92 (10) ◽  
pp. 3804-3816 ◽  
Author(s):  
John C. Byrd ◽  
Charlotte Shinn ◽  
Jamie K. Waselenko ◽  
Ephraim J. Fuchs ◽  
Teresa A. Lehman ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Cell Lines ◽  
Caspase 3 ◽  
Mononuclear Cells ◽  
P53 Protein ◽  
Lymphocytic Leukemia ◽  
Vitro Activity ◽  
Interleukin 4 ◽  
In Vitro Activity

Abstract Flavopiridol has been reported to induce apoptosis in lymphoid cell lines via downregulation of bcl-2. The in vitro activity of flavopiridol against human chronic lymphocytic leukemia (CLL) cells and potential mechanisms of action for inducing cytotoxicity were studied. The in vitro viability of mononuclear cells from CLL patients (n = 11) was reduced by 50% at 4 hours, 24 hours, and 4 days at a flavopiridol concentration of 1.15 μmol/L (95% confidence interval [CI] ±0.31), 0.18 μmol/L (95% CI ±0.04), and 0.16 μmol/L (95% CI ±0.04), respectively. Loss of viability in human CLL cells correlated with early induction of apoptosis. Exposure of CLL cells to 0.18 μmol/L of flavopiridol resulted in both decreased expression of p53 protein and cleavage of the caspase-3 zymogen 32-kD protein with the appearance of its 20-kD subunit. Contrasting observations of others in tumor cell lines, flavopiridol cytotoxicity in CLL cells did not correlate with changes in bcl-2 protein expression alterations. We evaluated flavopiridol’s dependence on intact p53 by exposing splenocytes from wild-type (p53+/+) and p53 null (p53−/−) mice that demonstrated no preferential cytotoxicity as compared with a marked differential with F-ara-a and radiation. Incubation of CLL cells with antiapoptotic cytokine interleukin-4 (IL-4) did not alter the LC50 of flavopiridol, as compared with a marked elevation noted with F-ara-a in the majority of patients tested. These data demonstrate that flavopiridol has significant in vitro activity against human CLL cells through activation of caspase-3, which appears to occur independently of bcl-2 modulation, the presence of IL-4, or p53 status. Such findings strongly support the early introduction of flavopiridol into clinical trials for patients with B-CLL.

scholarly journals Lactic dehydrogenase in normal and leukemia lymphocyte subpopulations: evidence for the presence of abnormal T cells and B cells in chronic lymphocytic leukemia

Blood ◽  
1981 ◽  
Vol 57 (2) ◽  
pp. 324-327 ◽  
Author(s):  
P Rambotti ◽  
S Davis
Keyword(s):  
T Cells ◽  
B Cells ◽  
Chronic Lymphocytic Leukemia ◽  
T Lymphocytes ◽  
B Lymphocytes ◽  
Lactic Dehydrogenase ◽  
Isozyme Pattern ◽  
Lymphocyte Subpopulations ◽  
Lymphocytic Leukemia ◽  
Ldh Activity

Abstract Lactic dehydrogenase (LDH) was quantitated and the isozyme pattern studied in lymphocyte subpopulations from normal people and patients with chronic lymphocytic leukemia (CLL). Normal T lymphocytes differed from normal B lymphocytes in having greater total LDH activity (597.2 versus 252.1). Total LDH activity in CLL T cells (347.1) was lower than normal T cells., but not significantly different than normal B cells. Total LDH activity in CLL B cells (124.6) was lower then normal B cells and normal T cells. The isozyme pattern of normal T lymphocytes showed a higher activity in the LDH-1 band (26.7% versus 5.4%) but showed a lower activity in LDH-5 band (4.3% versus 16.3%) compared to normal B cells. Chronic lymphocytic leukemia T cells could be distinguished from CLL B cells by a high LDH-5 band (22.3% versus 7.6%) and from normal T cells by a high LDH-5 band (22.3% versus 4.3%) and a low LDH-1 band (7.3% versus 26.7%). CLL B cells could be distinguished from normal B cells by a low LDH-5 band (7.6% versus 16.3%). Thus, the LDH isozyme pattern distinguishes normal T lymphocytes from normal B lymphocytes, and normal T and B lymphocytes from CLL T and B lymphocytes.

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