The chimeric anti-CD20 antibody rituximab induces apoptosis in B-cell chronic lymphocytic leukemia cells through a p38 mitogen activated protein–kinase–dependent mechanism

Blood ◽  
2002 ◽  
Vol 99 (4) ◽  
pp. 1314-1319 ◽  
Author(s):  
Irene Munk Pedersen ◽  
Anne Mette Buhl ◽  
Pia Klausen ◽  
Christian H. Geisler ◽  
Jesper Jurlander

Antibodies against CD20 can activate complement and induce antibody-dependent cellular cytotoxicity (ADCC) in B lymphocytes. In B-cell lines, such antibodies also induce apoptosis. In this study, the expression and function of CD20 on B-cell chronic lymphocytic leukemia (B-CLL) cells were analyzed. Flow cytometric analysis demonstrated that B-CLL cells express CD20 with a fluorescence intensity that is significantly weaker than that of normal CD5+ and CD5− B cells and that of malignant CD5− low-grade non-Hodgkin lymphoma cells. A small population of cells from healthy donors that have an expression pattern of CD5 and CD20 identical to that of B-CLL cells were identified, and this population was confirmed to be of T lineage, not B lineage. Culture of freshly isolated B-CLL cells in the presence of the chimeric anti-CD20 antibody rituximab and a cross-linking F(ab)2 fragment, resulted in dose- and time-dependent induction of apoptosis. The induction of apoptosis occurred under conditions in which the influence of complement activation and ADCC was negligible. Cross-linking of rituximab induced strong and sustained phosphorylation of the 3 mitogen activated protein (MAP) kinases c-Jun NH2-terminal protein kinase, extracellular signal–regulated kinase, and p38. Introduction of the p38 inhibitor SB203580 into the system completely blocked signaling downstream of p38, as evidenced by the absence of MAPKAP K2 activity, and significantly reduced the degree of anti-CD20–induced apoptosis. These results demonstrate that cross-linking of rituximab bound to CD20 on freshly isolated B-CLL cells induces apoptosis through a signaling pathway that is dependent on p38 MAP-kinase activation.

2008 ◽  
Vol 14 (12) ◽  
pp. 3984-3992 ◽  
Author(s):  
Elaine Willmore ◽  
Sarah L. Elliott ◽  
Tryfonia Mainou-Fowler ◽  
Geoffrey P. Summerfield ◽  
Graham H. Jackson ◽  
...  

Blood ◽  
1999 ◽  
Vol 94 (7) ◽  
pp. 2217-2224 ◽  
Author(s):  
U. Winkler ◽  
M. Jensen ◽  
O. Manzke ◽  
H. Schulz ◽  
V. Diehl ◽  
...  

Eleven patients with relapsed fludarabine-resistant B-cell chronic lymphocytic leukemia (CLL) or leukemic variants of low-grade B-cell non-Hodgkin’s lymphoma (NHL) were treated with the chimeric monoclonal anti-CD20 antibody rituximab (IDEC-C2B8). Peripheral lymphocyte counts at baseline varied from 0.2 to 294.3 × 109/L. During the first rituximab infusion, patients with lymphocyte counts exceeding 50.0 × 109/L experienced a severe cytokine-release syndrome. Ninety minutes after onset of the infusion, serum levels of tumor necrosis factor- (TNF-) and interleukin-6 (IL-6) peaked in all patients. Elevated cytokine levels during treatment were associated with clinical symptoms, including fever, chills, nausea, vomiting, hypotension, and dyspnea. Lymphocyte and platelet counts dropped to 50% to 75% of baseline values within 12 hours after the onset of the infusion. Simultaneously, there was a 5-fold to 10-fold increase of liver enzymes, d-dimers, and lactate dehydrogenase (LDH), as well as a prolongation of the prothrombin time. Frequency and severity of first-dose adverse events were dependent on the number of circulating tumor cells at baseline: patients with lymphocyte counts greater than 50.0 × 109/L experienced significantly more adverse events of National Cancer Institute (NCI) grade III/IV toxicity than patients with less than 50.0 × 109/L peripheral tumor cells (P= .0017). Due to massive side effects in the first patient treated with 375 mg/m2 in 1 day, a fractionated dosing schedule was used in all subsequent patients with application of 50 mg rituximab on day 1, 150 mg on day 2, and the rest of the 375 mg/m2 dose on day 3. While the patient with the leukemic variant of the mantle-cell NHL achieved a complete remission (9 months+) after treatment with 4 × 375 mg/m2 rituximab, efficacy in patients with relapsed fludarabine-resistant B-CLL was poor: 1 partial remission, 7 cases of stable disease, and 1 progressive disease were observed in 9 evaluable patients with CLL. On the basis of these data, different infusion schedules and/or combination regimens with chemotherapeutic drugs to reduce tumor burden before treatment with rituximab will have to be evaluated.


Leukemia ◽  
1997 ◽  
Vol 11 (8) ◽  
pp. 1253-1257 ◽  
Author(s):  
R Castejón ◽  
JA Vargas ◽  
M Briz ◽  
E Berrocal ◽  
Y Romero ◽  
...  

2004 ◽  
Vol 5 (6) ◽  
pp. 546-547 ◽  
Author(s):  
Despina Pantelidou ◽  
Costas Tsatalas ◽  
Dimitris Margaritis ◽  
Vasiliki Kaloutsi ◽  
Emmanuel Spanoudakis ◽  
...  

Blood ◽  
2000 ◽  
Vol 96 (2) ◽  
pp. 393-397 ◽  
Author(s):  
Shinichi Kitada ◽  
Juan M. Zapata ◽  
Michael Andreeff ◽  
John C. Reed

Compounds that inhibit protein kinases are currently undergoing clinical evaluation for the treatment of a variety of malignancies. The kinase inhibitors flavopiridol and 7 hydroxy-staurosporine (UCN-01) were examined for their effects on B-cell chronic lymphocytic leukemia (B-CLL) cells in vitro (n = 49). Flavopiridol and UCN-01 induced concentration-dependent apoptosis of most B-CLL samples tested, with greater than 50% cell killing occurring at concentrations of less than 1 μmol/L, and with flavopiridol displaying more potent activity than UCN-01. Flavopiridol (0.1 μmol/L) and UCN-01 (1 μmol/L) also induced striking decreases in the levels of the antiapoptosis proteins Mcl-1, X-linked inhibitor of apoptosis (XIAP), and BAG-1 in nearly all cases of B-CLL and of Bcl-2 in approximately half of B-CLL specimens evaluated. In contrast, expression of the proapoptotic proteins Bax and Bak was not significantly influenced by these kinase inhibitors. Flavopiridol-induced decreases in the levels of antiapoptosis proteins Mcl-1 and XIAP preceded apoptosis and were not substantially affected by the addition of caspase inhibitors to cultures. In contrast, UCN-01–stimulated decreases in antiapoptosis proteins were slower, occurred concurrently with apoptosis, and were partially prevented by caspase inhibitors. The findings suggest that flavopiridol and UCN-01 induce apoptosis of B-CLL cells through different mechanisms. The potent apoptotic activities of flavopiridol and UCN-01 against cultured B-CLL cells suggest that they may be effective as single agents in the treatment of B-CLL or for sensitizing B-CLL cells to conventional cytotoxic drugs.


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