Protein kinase inhibitors flavopiridol and 7-hydroxy-staurosporine down-regulate antiapoptosis proteins in B-cell chronic lymphocytic leukemia

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.

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

Abstract 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.


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

Blood ◽  
1988 ◽  
Vol 71 (4) ◽  
pp. 1012-1020 ◽  
Author(s):  
JS Moore ◽  
MB Prystowsky ◽  
RG Hoover ◽  
EC Besa ◽  
PC Nowell

The consistent occurrence of T cell abnormalities in patients with B cell chronic lymphocytic leukemia (B-CLL) suggest that the non- neoplastic host T cells may be involved in the pathogenesis of this B cell neoplasm. Because potential defects of immunoglobulin regulation are evident in B-CLL patients, we investigated one aspect of this by studying the T cell-mediated immunoglobulin isotype-specific immunoregulatory circuit in B-CLL. The existence of class-specific immunoglobulin regulatory mechanisms mediated by Fc receptor-bearing T cells (FcR + T) through soluble immunoglobulin binding factors (IgBFs) has been well established in many experimental systems. IgBFs can both suppress and enhance B cell activity in an isotype-specific manner. We investigated the apparently abnormal IgA regulation in a B-CLL patient (CLL249) whose B cells secrete primarily IgA in vitro. Enumeration of FcR + T cells showed a disproportionate increase in IgA FcR + T cells in the peripheral blood of this patient. Our studies showed that the neoplastic B cells were not intrinsically unresponsive to the suppressing component of IgABF produced from normal T cells, but rather the IgABF produced by the CLL249 host T cells was defective. CLL249 IgABF was unable to suppress IgA secretion by host or normal B cells and enhanced the in vitro proliferation of the host B cells. Size fractionation of both normal and CLL249 IgABF by gel-filtration high- performance liquid chromatography (HPLC) demonstrated differences in the ultraviolet-absorbing components of IgABF obtained from normal T cells v that from our patient with defective IgA regulation. Such T cell dysfunction may not be restricted to IgA regulation, since we have found similar expansion of isotype-specific FcR + T cells associated with expansion of the corresponding B cell clone in other patients with B-CLL. These data suggest that this T cell-mediated regulatory circuit could be significantly involved in the pathogenesis of B-CLL.


Blood ◽  
1987 ◽  
Vol 69 (6) ◽  
pp. 1667-1673 ◽  
Author(s):  
I Touw ◽  
L Dorssers ◽  
B Lowenberg

Abstract To determine the growth properties of B cell chronic lymphocytic leukemia (B CLL) and to identify possible abnormalities thereof, we examined the in vitro action of interleukin 2 (IL2) in four patients. Using radiolabeled IL2 and monoclonal antibodies reactive with IL2 membrane receptors we show that CLL cells, after their activation in vitro, express IL2 receptors of a high- as well as a low-affinity type, exactly as has been reported for normal T and B blasts. In three of the four reported cases, CLL proliferation (measured with 3H-thymidine incorporation) depended on the addition of phytohemagglutinin (PHA) to activate the cells and IL2 (optimal concentration, 10 to 100 U IL2/mL). In contrast, the cells of the fourth case of CLL (CLL-4) proliferated in an autonomous fashion, ie, without a need for PHA and IL2 in culture. Specific blocking of the IL2-binding sites with anti-IL2 receptor monoclonal antibodies almost completely inhibited the proliferation of these cells, which indicated that functional IL2 receptors were required for the autonomous proliferation. The demonstration of low concentrations of IL2 activity in the culture medium conditioned by the cells suggests that endogenous IL2 had been responsible for the spontaneous 3H-thymidine uptake by the CLL cells of patient 4. However, we were unable to extract IL2 mRNA from the cells (neither fresh nor after various in vitro incubations) in quantities detectable by Northern blot analysis that would prove that the CLL cells of patient 4 were actively synthesizing IL2 during culture. Thus, individual cases of B CLL are subject to variable growth regulation involving functional IL2 receptors on the cell surface: after activation with PHA the cells respond to exogenous IL2 in a fashion similar to normal B lymphocytes, or the cells are stimulated by endogenous IL2 (or an IL2-like activity) and do not require activation with PHA.


Blood ◽  
1984 ◽  
Vol 64 (3) ◽  
pp. 667-671 ◽  
Author(s):  
F Lauria ◽  
D Raspadori ◽  
S Tura

Abstract Abnormalities of T lymphocytes in B cell chronic lymphocytic leukemia (B-CLL) have been extensively documented by several immunologic investigations. Following recent studies pointing to the favorable effect of TP-1, a partially purified extract of calf thymus, on the T cell-mediated immunity of several diseases, including Hodgkin's disease, we have used monoclonal antibodies and the enriched T lymphocytes of 16 untreated B-CLL patients to evaluate the proportion of T cell subsets before and after the administration of TP-1. In addition, the proliferative response to phytohemagglutinin (PHA) and the helper function in a pokeweed mitogen (PWM) system were assessed. In ten cases, the effect of TP-1 was also studied in vitro by evaluating the same parameters before and after incubation of B-CLL T cells with the drug. The study demonstrated that in vivo administration of TP-1 increases significantly (P less than .001) the proportion of the defective helper/inducer T cell population (OKT4-positive cells) in B-CLL, leading to a near normal OKT4/OKT8 ratio. Furthermore, the improved phenotypic profile was accompanied by an increased proliferative response to PHA and, in particular, by a significant increase (P less than .01) of T helper capacity; this increase was, however, insufficient to enable the normalization of the serum immunoglobulin levels. The in vitro incubation of B-CLL T lymphocytes did not succeed in producing significant modifications in distribution and function.


Blood ◽  
2003 ◽  
Vol 101 (3) ◽  
pp. 1063-1070 ◽  
Author(s):  
Mohammad-Reza Rezvany ◽  
Mahmood Jeddi-Tehrani ◽  
Hans Wigzell ◽  
Anders Österborg ◽  
Håkan Mellstedt

Abstract T-cell receptor–B-variable (TCR-BV) gene usage and the CDR3 size distribution pattern were analyzed by reverse transcription–polymerase chain reaction (RT-PCR) in patients with B-cell chronic lymphocytic leukemia (B-CLL) to assess the T-cell repertoire. The use of TCR-BV families in CD4 and CD8 T cells stimulated with autologous activated leukemic cells was compared with that of freshly obtained blood T cells. Overexpression of individual TCR-BV families was found in freshly isolated CD4 and CD8 T cells. Polyclonal, oligoclonal, and monoclonal TCR-CDR3 patterns were seen within such overexpressed native CD4 and CD8 TCR-BV families. In nonoverexpressed TCR-BV families, monoclonal and oligoclonal populations were noted only within the CD8 subset. After in vitro stimulation of T cells with autologous leukemic B cells, analyses of the CDR3 length patterns showed that in expanded TCR-BV populations, polyclonal patterns frequently shifted toward a monoclonal/oligoclonal profile, whereas largely monoclonal patterns in native overexpressed TCR-BV subsets remained monoclonal. Seventy-five percent of CD8 expansions found in freshly obtained CD8 T cells further expanded on in vitro stimulation with autologous leukemic B cells. This suggests a memory status of such cells. In contrast, the unusually high frequency of CD4 T-cell expansions found in freshly isolated peripheral blood cells did not correlate positively to in vitro stimulation as only 1 of 9 expansions continued to expand. Our data suggest that leukemia cell–specific memory CD4 and CD8 T cells are present in vivo of patients with CLL and that several leukemia cell–associated antigens/epitopes are recognized by the patients' immune system, indicating that whole leukemia cells might be of preference for vaccine development.


Blood ◽  
2001 ◽  
Vol 97 (9) ◽  
pp. 2777-2783 ◽  
Author(s):  
Luisa Granziero ◽  
Paolo Ghia ◽  
Paola Circosta ◽  
Daniela Gottardi ◽  
Giuliana Strola ◽  
...  

Abstract In B-cell chronic lymphocytic leukemia (B-CLL), defective apoptosis causes the accumulation of mature CD5+ B cells in lymphoid organs, bone marrow (BM), and peripheral blood (PB). These cells are the progeny of a proliferating pool that feeds the accumulating compartment. The authors sought to determine which molecular mechanisms govern the proliferating pool, how they relate to apoptosis, and what the role is of the microenvironment. To begin to resolve these problems, the expression and modulation of the family of inhibitor of apoptosis proteins (IAPs) were investigated, with consideration given to the possibility that physiological stimuli, such as CD40 ligand (CD40L), available to B cells in the microenvironment, might modulate IAP expression. The in vitro data on mononuclear cells from PB or BM of 30 patients demonstrate that B-CLL cells on CD40 stimulation express Survivin and that Survivin is the only IAP whose expression is induced by CD40L. Through immunohistochemistry, in vivo Survivin expression in lymph node (LN) and BM biopsies was evaluated. In reactive LN, Survivin was detected only in highly proliferating germinal center cells. In LN from patients with B-CLL, Survivin was detected only in pseudofollicles. Pseudofollicle Survivin+ cells were actively proliferating and, in contrast to Survivin+ B cells found in normal GC, were Bcl-2+. In B-CLL BM biopsies, CD5+, Survivin+ cells were observed in clusters interspersed with T cells. These findings establish that Survivin controls the B-CLL proliferative pool interfacing apoptosis and that its expression may be modulated by microenvironmental stimuli.


Hematology ◽  
2012 ◽  
Vol 2012 (1) ◽  
pp. 88-96 ◽  
Author(s):  
Adrian Wiestner

Abstract Chronic lymphocytic leukemia (CLL) is a malignancy of mature B cells that depend on host factors in the tissue microenvironment for survival and proliferation. In vitro, CLL cells rapidly undergo apoptosis unless microenvironmental factors are provided that support their survival. Signaling pathways activated in the microenvironment in vivo include the B-cell receptor (BCR) and NF-κB pathways. Thus, CLL is a disease “addicted to the host” and is dependent on pathways that promote normal B-cell development, expansion, and survival; this is particularly true in the case of the BCR signaling cascade. Small-molecule inhibitors of kinases that are essential for BCR signal transduction abrogate the stimulating effects of the microenvironment on CLL cells. The orally administered tyrosine kinase inhibitors fostamatinib and ibrutinib and the phosphatidylinositol 3-kinase inhibitor GS-1101 have induced impressive responses in relapsed and refractory CLL patients, mostly with moderate side effects. Reductions in lymphadenopathy and splenomegaly are seen within weeks and are frequently accompanied by a transient rise in absolute lymphocyte count that is asymptomatic and probably the result of changes in CLL cell trafficking. This review discusses the biologic basis for kinase inhibitors as targeted therapy of CLL and summarizes the exciting early clinical experience with these agents.


Sign in / Sign up

Export Citation Format

Share Document