Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: UNIPROT:P42574 (caspase-3)
45,978 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Interleukin-21 (IL-21) is a member of the IL-2 cytokine family, which mediates proliferation or growth arrest and apoptosis of normal B cells, depending on their activation state. Here we demonstrate that surface IL-21 receptor (R) is expressed at variable levels by chronic lymphocytic leukemia (CLL) B cells freshly isolated from 33 different patients. IL-21R expression was up-regulated following cell stimulation via surface CD40. Therefore, IL-21 effects were more evident in CD40-activated CLL B cells. IL-21 induced an early signaling cascade in CLL B cells, which included JAK-1 and JAK-3 autophosphorylation and tyrosine phosphorylation of STAT-1, STAT-3, and STAT-5. IL-21 signaling failed to stimulate CLL B-cell proliferation, but induced their apoptosis. In addition, IL-21 counteracted the proliferative and antiapoptotic signals delivered by IL-15 to CLL B cells. IL-21-mediated apoptosis involved activation of caspase-8 and caspase-3, cleavage of Bid to its active form t-Bid, and cleavage of PARP and of p27Kip-1. Recent data indicate that CLL B cells require interaction with the microenvironment for their survival and expansion. The present findings thus provide a set of new mechanisms involved in the balance between cell-survival and apoptotic signals in CLL B cells.
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PMID:Interleukin-21 receptor (IL-21R) is up-regulated by CD40 triggering and mediates proapoptotic signals in chronic lymphocytic leukemia B cells. 1639 Oct 14

This study was undertaken to characterize preclinical cytotoxic interactions for human malignancies between the multikinase inhibitor sorafenib (BAY 43-9006) and proteasome inhibitors bortezomib or MG132. Multiple tumor cell lines of varying histiotypes, including A549 (lung adenocarcinoma), 786-O (renal cell carcinoma), HeLa (cervical carcinoma), MDA-MB-231 (breast), K562 (chronic myelogenous leukemia), Jurkat (acute T-cell leukemia), MEC-2 (B-chronic lymphocytic leukemia), and U251 and D37 (glioma), as well as cells derived from primary human glioma tumors that are likely a more clinically relevant model were treated with sorafenib or bortezomib alone or in combination. Sorafenib and bortezomib synergistically induced a marked increase in mitochondrial injury and apoptosis, reflected by cytochrome c release, caspase-3 cleavage, and poly(ADP-ribose) polymerase degradation in a broad range of solid tumor and leukemia cell lines. These findings were accompanied by several biochemical changes, including decreased phosphorylation of vascular endothelial growth factor receptor-2, platelet-derived growth factor receptor-beta, and Akt and increased phosphorylation of stress-related c-Jun NH2-terminal kinase (JNK). Inhibition of Akt was required for synergism, as a constitutively active Akt protected cells against apoptosis induced by the combination. Alternatively, the JNK inhibitor SP600125 could also protect cells from apoptosis induced by the combination, indicating that both inhibition of Akt and activation of JNK were required for the synergism. These findings show that sorafenib interacts synergistically with bortezomib to induce apoptosis in a broad spectrum of neoplastic cell lines and show an important role for the Akt and JNK pathways in mediating synergism. Further clinical development of this combination seems warranted.
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PMID:Cytotoxic synergy between the multikinase inhibitor sorafenib and the proteasome inhibitor bortezomib in vitro: induction of apoptosis through Akt and c-Jun NH2-terminal kinase pathways. 1698 72

The thiocarbamate drug disulfiram has been used for decades in the treatment of alcohol abuse. Disulfiram induces apoptosis in a number of tumor cell lines and was recently by us proposed to act as a 26S proteasome inhibitor. In this work we characterized disulfiram in vitro with regard to tumor-type specificity, possible mechanisms of action and drug resistance and cell death in human tumor cell lines and in 78 samples of tumor cells from patients using the fluorometric microculture cytotoxicity assay and the automated fluorescence-imaging microscope ArrayScan((R)). Disulfiram induced cytotoxicity in a biphasic pattern in both cell lines and patient tumor cells. Disulfiram induced apoptosis as measured by cell membrane permeability, nuclear fragmentation/condensation and caspase-3/7 activation using high content screening assays. For many of the cell lines tested disulfiram was active in sub-micromolar concentrations. When comparing the logIC(50) patterns with other cytotoxic agents, disulfiram showed low correlation (R<0.5) with all drugs except lactacystin (R=0.69), a known proteasome inhibitor, indicating that the two substances may share mechanistic pathways. Disulfiram was more active in hematological than in solid tumor samples, but substantial activity was observed in carcinomas of the ovary and the breast and in non-small cell lung cancer. Disulfiram also displayed higher cytotoxic effect in cells from chronic lymphocytic leukemia than in normal lymphocytes (p<0.05), which may indicate some tumor selectivity. These results together with large clinical experience and relatively mild side effects encourage clinical studies of disulfiram as an anti-cancer agent.
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PMID:Pharmacological profiling of disulfiram using human tumor cell lines and human tumor cells from patients. 1702 67

CXCL13/CXCR5 and CCL19/CCR7 play a quite important role in normal physiological conditions, but the functions of both chemokine/receptor pairs in pathophysiological events are not well-investigated. We have investigated expression and functions of CXCL13/CXCR5 and CCL19/CCR7 in CD23+CD5+ and CD23+CD5- B cells from cord blood (CB) and patients with B cell lineage acute or chronic lymphocytic leukemia (B-ALL or B-CLL). CXCR5 and CCR7 are selectively expressed on B-ALL, B-CLL, and CB CD23+CD5+ B cells at high frequency, but not on CD23+CD5- B cells. Although no significant chemotactic responsiveness was observed, CXCL13 and CCL19 cooperatively induce significant resistance to TNF-alpha-mediated apoptosis in B-ALL and B-CLL CD23+CD5+ B cells, but not in the cells from CB. B-ALL and B-CLL CD23+CD5+ B cells express elevated levels of paternally expressed gene 10 (PEG10). CXCL13 and CCL19 together significantly up-regulate PEG10 expression in the same cells. We have found that CXCL13 and CCL19 together by means of activation of CXCR5 and CCR7 up-regulate PEG10 expression and function, subsequently stabilize caspase-3 and caspase-8 in B-ALL and B-CLL CD23+CD5+ B cells, and further rescue the cells from TNF-alpha-mediated apoptosis. Therefore, we suggest that normal lymphocytes, especially naive B and T cells, use CXCL13/CXCR5 and CCL19/CCR7 for migration, homing, maturation, and cell homeostasis as well as secondary lymphoid tissues organogenesis. In addition, certain malignant cells take advantages of CXCL13/CXCR5 and CCL19/CCR7 for infiltration, resistance to apoptosis, and inappropriate proliferation.
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PMID:CXC chemokine ligand 13 and CC chemokine ligand 19 cooperatively render resistance to apoptosis in B cell lineage acute and chronic lymphocytic leukemia CD23+CD5+ B cells. 1708 84

In this study we attempted to assess interactions of thalidomide with fludarabine in terms of their effect on DNA damage and apoptosis of chronic lymphocytic leukemia (CLL) cells. The experiments were done in ex vivo short-term cell cultures of peripheral blood cells from newly diagnosed untreated patients. We analyzed phosphorylation of histone H2AX on Ser139 (gammaH2AX), reporter of DNA damage, and expression of activated caspase-3, as a marker of apoptosis. Modest increase in expression of gammaH2AX caused by thalidomide was observed in samples of some analyzed patients. The increase in expression of gammaH2AX was also seen in leukemic TK6 cells treated with thalidomide. While treatment of CLL cells with thalidomide alone had no significant effect on apoptosis the treatment with thalidomide+fludarabine had greater than the additive effect on frequency of apoptotic cells. The data suggest that oxidative DNA damage likely induced by thalidomide sensitizes CLL cells to undergo apoptosis in response to fludarabine.
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PMID:Thalidomide induces phosphorylation of histone H2AX and increases rate of apoptosis caused by fludarabine in malignant lymphocytes of chronic lymphocytic leukemia in short-term cell cultures. 1897 29

Chronic lymphocytic leukemia (CLL) cells are characterized by defective apoptosis which leads to their extended survival. Arsenic trioxide (As(2)O(3)) was reported to induce cell death in many malignant cells, but the specific pathway of As(2)O(3)-induced apoptosis/necrosis remains controversial. Our aim was to determine if As(2)O(3) kills CLL cells through apoptosis and whether this is accompanied by reduction in Bcl-2 levels. Cells from nine patients with CLL were incubated with increasing concentrations of As(2)O(3) (0.5-2 microM) for 2, 7, or 14 days. Cells viability was measured using Alamar Blue assay and apoptosis using human Annexin V-FITC and propidium iodine (PI) kit (BMS306FI; Bender MedSystems, Vienna, Austria). Intracellular Bcl-2, Bax, and caspase-3 levels were measured by flow cytometry. As(2)O(3) significantly reduced CLL cell viability (P < 0.01) and induced apoptotic cell death in a time- and dose-dependent manner. After 7 days, CLL cells showed a significant decrease in mean fluorescence intensity (MFI) of Bcl-2 on flow cytometry study. Bax and caspase-3 levels showed significant decrease in MFI only after prolonged incubations (7 and 14 days) and mostly at higher concentrations of As(2)O(3). The mechanism underlying the reduction in viability of CLL cells incubated with As(2)O(3) is mediated by induction of apoptosis maybe through the down-regulation of Bcl-2. Further studies are needed to elucidate the potential therapeutic role of As(2)O(3) in CLL.
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PMID:Arsenic-trioxide-induced apoptosis of chronic lymphocytic leukemia cells. 1920 92

We studied the actions of 2-phenylacetylenesulfonamide (PAS) on B-chronic lymphocytic leukemia (CLL) cells. PAS (5-20 microM) initiated apoptosis within 24 hours, with maximal death at 48 hours asassessed by morphology, cleavage of poly(ADP-ribose) polymerase (PARP), caspase 3 activation, and annexin V staining. PAS treatment induced Bax proapoptotic conformational change, Bax movement from the cytosol to the mitochondria, and cytochrome c release, indicating that PAS induced apoptosis via the mitochondrial pathway. PAS induced approximately 3-fold up-regulation of proapoptotic Noxa protein and mRNA levels. In addition, Noxa was found unexpectedly to be bound to Bcl-2 in PAS-treated cells. PAS treatment of CLL cells failed to up-regulate p53, suggesting that PAS induced apoptosis independently of p53. Furthermore, PAS induced apoptosis in CLL isolates with p53 gene deletion in more than 97% of cells. Normal B lymphocytes were as sensitive to PAS-induced Noxa up-regulation and apoptosis as were CLL cells. However, both T lymphocytes and bone marrow hematopoietic progenitor cells were relatively resistant to PAS. Our data suggest that PAS may represent a novel class of drug that induces apoptosis in CLL cells independently of p53 status by a mechanism involving Noxa up-regulation.
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PMID:2-Phenylacetylenesulfonamide (PAS) induces p53-independent apoptotic killing of B-chronic lymphocytic leukemia (CLL) cells. 3143 19

B-cell chronic lymphocytic leukemia (B-CLL) is characterized by accumulation of mature monoclonal CD5+ B cells. The disease results mainly from a failure of cells to undergo apoptosis, a process largely influenced by the existence of constitutively activated components of B-cell receptor signaling and the deregulated expression of anti-apoptotic molecules. Recent evidence pointing to a critical role of spleen tyrosine kinase (Syk) in ligand-independent BCR signaling prompted us to examine its role in primary B-CLL cell survival. We demonstrate that pharmacological inhibition of constitutive Syk activity and silencing by siRNA led to a dramatic decrease of cell viability in CLL samples (n=44), regardless of clinical and biological status and induced typical apoptotic cell death with mitochondrial failure followed by caspase 3-dependent cell death. We also provide functional and biochemical evidence that Syk regulated B-CLL cell survival through a novel pathway involving PKCdelta and a proteasome-dependent regulation of the anti-apoptotic protein Mcl-1. Together, our observations are consistent with a model wherein PKCdelta downstream of Syk stabilizes Mcl-1 through inhibitory phosphorylation of GSK3 by Akt. We conclude that Syk constitutes a key regulator of B-CLL cell survival, emphasizing the clinical utility of Syk inhibition in hematopoietic malignancies.
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PMID:The tyrosine kinase Syk regulates the survival of chronic lymphocytic leukemia B cells through PKCdelta and proteasome-dependent regulation of Mcl-1 expression. 1958 35

Evasion of apoptosis is a hallmark of chronic lymphocytic leukemia (CLL), calling for new strategies to bypass resistance. Here, we provide first evidence that small-molecule X-linked inhibitor of apoptosis (XIAP) inhibitors in combination with the death receptor ligand tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) present a novel approach to trigger apoptosis in CLL, including subgroups with resistant disease or unfavorable prognosis. XIAP, cellular IAP (cIAP) 1, and cIAP2 are expressed at high levels in primary CLL samples. Proof-of-concept studies in CLL cell lines show that subtoxic concentrations of XIAP inhibitors significantly enhance TRAIL-induced apoptosis and also sensitize for CD95-mediated apoptosis. Importantly also in primary CLL samples, XIAP inhibitor acts in concert with TRAIL to trigger apoptosis in 18 of 27 (67%) cases. This XIAP inhibitor-induced and TRAIL-induced apoptosis involves caspase-3 activation and is blocked by the caspase inhibitor zVAD.fmk. The cooperative interaction of XIAP inhibitor and TRAIL is even evident in distinct subgroups of patients with poor prognostic features (i.e., with 17p deletion, TP53 mutation, chemotherapy-refractory disease, or unmutated V(H) genes). Interestingly, cases with unmutated V(H) genes were significantly more sensitive to XIAP inhibitor-induced and TRAIL-induced apoptosis compared with V(H) gene-mutated samples, pointing to a role of B-cell receptor signaling in apoptosis regulation. By showing that XIAP inhibitors in combination with TRAIL present a new strategy to trigger apoptosis even in resistant forms and poor prognostic subgroups of CLL, our findings have important implications for the development of apoptosis-based therapies in CLL.
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PMID:A novel paradigm to trigger apoptosis in chronic lymphocytic leukemia. 1992 Feb

Mechanisms behind carcinogenesis and resistance of tumor cells to treatment regimes remain elusive. The major stress proteins Hsp72, Hsp90, and Hsp27 are credible candidates to provide this resistance, as their overexpression in many cancer types is well documented. In addition to being present inside tumor cells, where they confer resistance to apoptosis, Hsp72, in particular, is presented externally, embedded in the cell membrane of cancer cells. This study aimed to investigate the localization of Hsp72, Hsp90, and Hsp27 in leukocytes from patients with CLL and age-matched control subjects. CLL patients were found to express significantly higher levels of iHsp90 (CLL=2463 MFI; control=748 MFI) and iHsp27 (CLL=2190 MFI; control=1031 MFI) in lymphocytes than that expressed by lymphocytes from control subjects. Furthermore, expression of iHsp90 was shown to be related to stage of disease, and expression of iHsp27 correlated with levels of active caspase-3. Patients were found to express very high levels or very low levels of sHsp72 and iHsp72 in CD5(+)/CD19(+) cells, although surface and intracellular datasets did not correlate. Levels of extracellular Hsp72 circulating in the serum were found to correlate with internal levels of Hsp72 and were also found to be significantly lower in patients receiving corticosteroid treatment than in patients not receiving corticosteroid treatment. Finally, analysis of the number of circulating Tregs revealed significantly elevated numbers in CLL patients compared with control subjects.
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PMID:Differential heat shock protein localization in chronic lymphocytic leukemia. 2000 7


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