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Abstract
The role of cyclic AMP (cAMP) as second messenger in erythropoiesis has been suggested in the early 1980s. However, careful analysis showed that cAMP is not generated in direct response to the main erythropoiesis-controlling cytokines such as erythropoietin (Epo). As a result, cAMP disappeared from the central stage in research of erythropoiesis. Instead, other signal transduction pathways, including the Ras/extracellular regulated kinase (ERK)-pathway, the phosphatidylinositol 3-kinase (P13K) and the signal transducer and activator of transcription (STAT5)-pathways, have been found and explored. In concert, these signaling pathways control the transcriptional machinery of erythroid cells. Although cAMP is not directly generated in response to Epo stimulation, it has recently been demonstrated that increased cAMP-levels and in particular the cAMP-dependent protein kinase A (PKA) can modulate erythroid signal transduction pathways. In some cases, like the ERK-signaling pathway, PKA affects signal transduction by regulating the balance between specific phosphatases and kinases. In other cases, such as the STAT5 pathway, PKA enhances Epo signaling by inducing recruitment of additional co-regulators of transcription. In addition to STAT5, PKA also activates other transcription factors that are required for erythroid gene expression. This review discusses the impact of cAMP/PKA on Epo-mediated signaling pathways and summarizes the role of cAMP in malignant erythropoiesis.
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Birkenkamp KU, Geugien M, Schepers H, Westra J, Lemmink HH, Vellenga E. Constitutive NF-kappaB DNA-binding activity in AML is frequently mediated by a Ras/PI3-K/PKB-dependent pathway. Leukemia 2004; 18:103-12. [PMID: 14574326 DOI: 10.1038/sj.leu.2403145] [Citation(s) in RCA: 112] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
In the present study, we aimed to elucidate the mechanism responsible for constitutive NF-kappaB DNA-binding activity in AML cells. Intervening in aberrant signaling pathway provides a rational approach for in vivo targeting of AML cells. Constitutive NF-kappaB DNA-binding activity was observed in 16 of 22 (73%) investigated AML cases and was, in general, associated with resistance to spontaneous apoptosis. Indeed, inhibition of NF-kappaB activity by the NF-kappaB inhibitor SN-50 peptide resulted in enhanced chemotherapy-induced apoptosis. In the majority of cases, constitutive NF-kappaB activity was mediated by a Ras/PI3 kinase (PI3-K)/protein kinase B (PKB)-mediated pathway. The PI3-K inhibitor Ly294002 and the Ras inhibitor L-744832 both inhibited PKB phosphorylation and NF-kappaB DNA-binding activity. The constitutive activation of Ras GTP-ase was caused by mutations in the gene encoding for N-Ras in 29% of the cases. The constitutive NF-kappaB activity could so far not be ascribed to the autocrine production of growth factors or to mutations in the Flt3 receptor, since anti-GM-CSF, -IL-1, -IL6, -TNFalpha or the tyrosine kinase inhibitor AG1296 did not affect the NF-kappaB DNA-binding activity. The present study demonstrates that Ras activation is an important pathway for triggering the NF-kappaB pathway in AML cells.
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203
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Plasschaert SLA, Kamps WA, Vellenga E, de Vries EGE, de Bont ESJM. Prognosis in childhood and adult acute lymphoblastic leukaemia: a question of maturation? Cancer Treat Rev 2004; 30:37-51. [PMID: 14766125 DOI: 10.1016/s0305-7372(03)00140-3] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Acute lymphoblastic leukaemia (ALL) is a disease diagnosed in children as well as adults. Progress in the treatment of ALL has led to better survival rates, however, children have benefited more from improved treatment modalities than adults. Recent evidence has underscored that the difference in characteristics and biology of adult versus childhood ALL might be the result of a different origin. According to the two-hit paradigm of Knudson, to develop cancer two genetic events are necessary. It has been suggested, that in childhood ALL the first genetic event happens in the more mature lymphoid committed progenitor cells, whereas in adult ALL the first hit occurs in multipotent stem cells. This review compares patient characteristics, the extent of the disease, leukaemic cell characteristics and treatment between childhood and adult ALL. This is discussed in relation to the hypothesis that the maturation stage of the cells, from which the leukaemia arises, is responsible for the differential behaviour of adult and childhood ALL.
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204
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Houwerzijl EJ, Blom NR, van der Want JJL, Esselink MT, Koornstra JJ, Smit JW, Louwes H, Vellenga E, de Wolf JTM. Ultrastructural study shows morphologic features of apoptosis and para-apoptosis in megakaryocytes from patients with idiopathic thrombocytopenic purpura. Blood 2004; 103:500-6. [PMID: 12969975 DOI: 10.1182/blood-2003-01-0275] [Citation(s) in RCA: 204] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
To investigate whether altered megakaryocyte morphology contributes to reduced platelet production in idiopathic thrombocytopenic purpura (ITP), ultrastructural analysis of megakaryocytes was performed in 11 ITP patients. Ultrastructural abnormalities compatible with (para-)apoptosis were present in 78% +/- 14% of ITP megakaryocytes, which could be reversed by in vivo treatment with prednisone and intravenous immunoglobulin. Immunohistochemistry of bone marrow biopsies of ITP patients with extensive apoptosis showed an increased number of megakaryocytes with activated caspase-3 compared with normal (28% +/- 4% versus 0%). No difference, however, was observed in the number of bone marrow megakaryocyte colony-forming units (ITP, 118 +/- 93/105 bone marrow cells; versus controls, 128 +/- 101/105 bone marrow cells; P =.7). To demonstrate that circulating antibodies might affect megakaryocytes, suspension cultures of CD34+ cells were performed with ITP or normal plasma. Morphology compatible with (para-)apoptosis could be induced in cultured megakaryocytes with ITP plasma (2 of 10 samples positive for antiplatelet autoantibodies). Finally, the plasma glycocalicin index, a parameter of platelet and megakaryocyte destruction, was increased in ITP (57 +/- 70 versus 0.7 +/- 0.2; P =.009) and correlated with the proportion of megakaryocytes showing (para-) apoptotic ultrastructure (P =.02; r = 0.7). In conclusion, most ITP megakaryocytes show ultrastructural features of (para-) apoptosis, probably due to action of factors present in ITP plasma.
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Oude Nijhuis CSM, Gietema JA, Vellenga E, Daenen SMGJ, De Bont ESJM, Kamps WA, Groen HJM, van der Jagt EJ, van der Graaf WTA. Routine radiography does not have a role in the diagnostic evaluation of ambulatory adult febrile neutropenic cancer patients. Eur J Cancer 2004; 39:2495-8. [PMID: 14602135 DOI: 10.1016/j.ejca.2003.06.002] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Cancer patients treated with chemotherapy are susceptible to bacterial infections. When an adult patient presents with febrile neutropenia, standard diagnostic care includes physical examination, laboratory diagnostics, chest X-ray (CXR) and sinus radiography. However, the yield of routine radiography in the diagnostic evaluation of ambulatory adult febrile neutropenic patients with normal findings at their physical examination is questionable. Two CXRs and one sinus X-ray were obtained in 109 and 106 febrile neutropenic episodes after chemotherapy in ambulatory adult patients who had no clinical signs suggesting pulmonary infection or sinusitis. We found that in only two of 109 (1.8%; 95% Confidence Interval (CI): 0.3-5.8%) febrile neutropenic episodes without clinical signs of new pulmonary disease, the CXR showed a consolidation suggesting pneumonia. In addition, in five of 88 (5.7%; 95% CI: 2.2-12.0%) febrile episodes in asymptomatic patients, sinus X-ray suggested sinusitis. In none of these seven episodes was a change of antibiotic therapy necessary. In the absence of clinical signs indicating pneumonia or sinusitis, the yield of CXR and sinus radiography in ambulatory adult cancer patients presenting with febrile neutropenia is minimal; CXR and sinus radiography should no longer be performed on a routine basis.
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Schot B, van Imhoff G, Pruim J, Sluiter W, Vaalburg W, Vellenga E. Predictive value of early 18F-fluoro-deoxyglucose positron emission tomography in chemosensitive relapsed lymphoma. Br J Haematol 2003; 123:282-7. [PMID: 14531910 DOI: 10.1046/j.1365-2141.2003.04593.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
18F-fluoro-deoxyglucose (FDG) positron emission tomography (PET) might be a better tool than computerized tomography (CT) in predicting long-term treatment outcome in patients with relapsed chemosensitive lymphoma who are candidates for autologous stem cell transplantation (ASCT). We studied patients with recurrent or persistent aggressive non-Hodgkin's lymphoma (NHL) and Hodgkin's disease (HD), who were treated with three courses of second-line induction chemotherapy [DHAP-VIM (dexamethasone, cytarabine, cisplatin followed by etoposide, iphosphamide and methotrexate)-DHAP], followed by myeloablative therapy and ASCT if chemosensitive. FDG-PET was performed in parallel to conventional diagnostic methods before starting, and after two courses of, second-line therapy. Of 68 relapsed lymphoma patients, 46 chemosensitive patients (33 NHL and 13 HD) were included, of whom 39 were transplanted. After DHAP-VIM, the second PET scan was normalized in 15/46 patients; progression-free survival at 2 years was 62% for PET-negative patients versus 32% for PET-positive patients (P = 0.048). The relative risk for progressive disease in patients with < 90% intensity reduction was 2.85 (95% confidence interval 1.15-7.05, P = 0.018). Early FDG-PET may help to predict the long-term treatment outcome of ASCT in chemosensitive patients with relapsed lymphoma and identify those patients who need extra or alternative treatment. Disappearance or > 90% reduction of intensity of abnormal FDG uptake after two courses of reinduction therapy was correlated with a favourable outcome.
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207
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Plasschaert SLA, van der Kolk DM, de Bont ESJM, Kamps WA, Morisaki K, Bates SE, Scheffer GL, Scheper RJ, Vellenga E, de Vries EGE. The role of breast cancer resistance protein in acute lymphoblastic leukemia. Clin Cancer Res 2003; 9:5171-7. [PMID: 14613996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/27/2023]
Abstract
PURPOSE Overexpression of the transporter ABCG2, also known as breast cancer resistance protein and mitoxantrone resistance protein, can confer resistance to a variety of cytostatic drugs, such as mitoxantrone, topotecan, doxorubicin, and daunorubicin. This study analyzes the ABCG2 expression and activity in 46 human de novo acute lymphoblastic leukemia B- and T-lineage (ALL) samples. EXPERIMENTAL DESIGN ABCG2 expression was measured flow cytometrically with the BXP-34 monoclonal antibody. ABCG2 functional activity was determined flow cytometrically by measuring mitoxantrone accumulation in combination with the ABCG2 inhibitor fumitremorgin C (FTC). To determine a possible effect of the transporters P-glycoprotein and multidrug resistance-associated protein (MRP1 and MRP2) on mitoxantrone accumulation, the accumulation was investigated in the presence of the P-glycoprotein inhibitor PSC 833 and MRP inhibitor MK-571. The ABCG2 gene was sequenced to investigate the amino acid at position 482. RESULTS In B-lineage ALL (n = 23), the median BXP-34:IgG1 ratio was higher, namely 2.4 (range, 1.7-3.7), than in T-lineage ALL (n = 23; 1.9; range, 1.2-6.6; P = 0.003). The addition of FTC to mitoxantrone treatment caused a median increase in mitoxantrone accumulation of 21% (range, 0-140%) in B-lineage ALL. In T-lineage ALL, this FTC effect was less pronounced (5%; range, 0-256%; P = 0.013). The influence of FTC on mitoxantrone accumulation correlated with ABCG2 protein expression (r = 0.52; P < 0.001; n = 43). The increase in mitoxantrone accumulation, when FTC was added to cells treated with both PSC 833 and MK-571, correlated with the ABCG2 expression in B-lineage ALL but not in T-lineage ALL. Sequencing the ABCG2 gene revealed no ABCG2 mutation at position 482 in patients who accumulated more rhodamine after FTC. CONCLUSIONS This study shows that ABCG2 is expressed higher and functionally more active in B-lineage than in T-lineage ALL.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- ATP Binding Cassette Transporter, Subfamily G, Member 2
- ATP-Binding Cassette Transporters/antagonists & inhibitors
- ATP-Binding Cassette Transporters/metabolism
- Adolescent
- Adult
- Aged
- Antibodies, Monoclonal
- Antineoplastic Agents/pharmacology
- Bronchodilator Agents/pharmacology
- Burkitt Lymphoma/drug therapy
- Burkitt Lymphoma/metabolism
- Burkitt Lymphoma/pathology
- Child
- Child, Preschool
- Cyclosporins/pharmacology
- Drug Resistance, Multiple
- Drug Resistance, Neoplasm
- Female
- Flow Cytometry
- Gene Expression Regulation, Leukemic
- Gene Expression Regulation, Neoplastic
- Humans
- Indoles/pharmacology
- Infant
- Leukemia-Lymphoma, Adult T-Cell/drug therapy
- Leukemia-Lymphoma, Adult T-Cell/metabolism
- Leukemia-Lymphoma, Adult T-Cell/pathology
- Male
- Middle Aged
- Mitoxantrone/metabolism
- Multidrug Resistance-Associated Proteins/antagonists & inhibitors
- Multidrug Resistance-Associated Proteins/metabolism
- Neoplasm Proteins/antagonists & inhibitors
- Neoplasm Proteins/metabolism
- Propionates/pharmacology
- Quinolines/pharmacology
- Tumor Cells, Cultured/drug effects
- Tumor Cells, Cultured/metabolism
- Tumor Cells, Cultured/pathology
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208
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Schepers H, Geugien M, Eggen BJL, Vellenga E. Constitutive cytoplasmic localization of p21(Waf1/Cip1) affects the apoptotic process in monocytic leukaemia. Leukemia 2003; 17:2113-21. [PMID: 12931225 DOI: 10.1038/sj.leu.2403106] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In the present study, we analysed the expression and localization of p21(Waf1/Cip1) in normal and malignant haematopoietic cells. We demonstrate that in normal monocytic cells, protein kinase C (PKC)-induced p21 gene activation, which is nuclear factor-kappaB (NF-kappaB) independent, results in predominantly cytoplasmic localized p21 protein. In acute monocytic leukaemia (M4, M5), monocytic blasts (N=12) show constitutive cytoplasmic p21 expression in 75% of the cases, while in myeloid leukaemic blasts (N=10), low nuclear and cytoplasmic localization of p21 could be detected, which is also PKC dependent. Constitutive p21 expression in monocytic leukaemia might have important antiapoptotic functions. This is supported by the finding that in U937 cells overexpressing p21, VP16-induced apoptosis is significantly reduced (20.0+/-0.9 vs 55.8+/-3.8%, P<0.01, N=5), reflected by a reduced phosphorylation of p38 and JNK. Similarly, AML blasts with high cytoplasmic p21 were less sensitive to VP16-induced apoptosis as compared to AML cases with low or undetectable p21 expression (42.25 vs 12.3%, P<0.01). Moreover, complex formation between p21 and ASK1 could be demonstrated in AML cells, by means of coimmunoprecipitation. In summary, these results indicate that p21 has an antiapoptotic role in monocytic leukaemia, and that p21 expression is regulated in a PKC-dependent and NF-kappaB-independent manner.
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209
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Oude Nijhuis CSM, Vellenga E, Daenen SMGJ, van der Graaf WTA, Gietema JA, Groen HJM, Kamps WA, de Bont ESJM. Lipopolysaccharide-binding protein: a possible diagnostic marker for Gram-negative bacteremia in neutropenic cancer patients. Intensive Care Med 2003; 29:2157-2161. [PMID: 14569424 DOI: 10.1007/s00134-003-2026-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2003] [Accepted: 09/08/2003] [Indexed: 11/26/2022]
Abstract
OBJECTIVE Cancer patients with febrile neutropenia after chemotherapy have a variable risk of bacterial infection. Especially Gram-negative bacteremia is associated with high mortality and/or morbidity. Early diagnosis of patients with Gram-negative bacteremia at the onset of febrile neutropenia is potentially useful in tailoring therapy. DESIGN AND SETTING Prospective study at the Department of Pediatric Oncology and Internal Medicine of a university hospital. PATIENTS Were analyzed 66 febrile neutropenic episodes in 57 adults and children. Patients were divided into four groups: those with Gram-negative bacteremia, Gram-positive bacteremia, clinical sepsis, or fever of unknown origin. MEASUREMENTS AND RESULTS Plasma lipopolysaccharide-binding protein (LBP) and C-reactive protein (CRP) concentrations were determined. LBP at the onset of febrile neutropenia was significantly higher in patients with Gram-negative bacteremia than those with fever of unknown origin and those with Gram-positive bacteremia. Using a cutoff value for LBP proved to have much greater sensitivity, specificity, and positive and negative predictive value for Gram-negative bacteremia than the best cutoff value for CRP. CONCLUSIONS An initial high LBP level might predict Gram-negative bacteremia in cancer patients with febrile neutropenia. These results may have potential clinical impact by allowing therapy to be initiated for these patients at a very early stage.
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210
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van Everdink WJ, Baranova A, Lummen C, Tyazhelova T, Looman MWG, Ivanov D, Verlind E, Pestova A, Faber H, van der Veen AY, Yankovsky N, Vellenga E, Buys CHCM. RFP2, c13ORF1, and FAM10A4 are the most likely tumor suppressor gene candidates for B-cell chronic lymphocytic leukemia. ACTA ACUST UNITED AC 2003; 146:48-57. [PMID: 14499696 DOI: 10.1016/s0165-4608(03)00126-2] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Occurrence of 13q14 deletions between D13S273 and D13S25 in B-cell chronic lymphocytic leukemia (B-CLL) suggests that the region contains a tumor suppressor gene. We constructed a PAC/cosmid contig largely corresponding to a 380-kb 13q14 YAC insert that we found deleted in a high proportion of B-CLL patients. We found seven genes by exon trapping, cDNA screening and analysis/cDNA extension of known expressed sequence tags. One appeared to originate from another region of 13q. Recent publications have focused on two of the genes that most likely do not have a tumor suppressor role. This study evaluates the remaining four genes in the region by mutation scanning and theoretical analysis of putative encoded products. No mutations suggestive of a pathogenic effect were found. The 13q14 deletions may be a consequence of an inherent instability of the region, an idea supported by our finding of a considerable proportion of AluY repeats. Deletion of putative enhancer sequences and/or genes in the region may result in an inactivation of tumor suppression by a haploinsufficiency mechanism. We conclude that RFP2, c13ORF1, and a chromosome 13-specific ST13-like gene, FAM10A4, are the most likely candidates for such a type of B-CLL TSG.
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211
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Fuhler GM, Hooijenga F, Drayer AL, Vellenga E. Reduced expression of flavocytochrome b558, a component of the NADPH oxidase complex, in neutrophils from patients with myelodysplasia. Exp Hematol 2003; 31:752-9. [PMID: 12962720 DOI: 10.1016/s0301-472x(03)00188-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
OBJECTIVE Patients with myelodysplasia (MDS) show a disturbed production of ROS in response to N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP) in granulocyte-macrophage colony-stimulating factor (GM-CSF)-primed neutrophils. Because generation of ROS is mediated by the NADPH oxidase complex, a component of which is flavocytochrome b558, we investigated whether the expression of flavocytochrome b558 in neutrophils from MDS patients is affected. MATERIAL AND METHODS Neutrophils were stimulated with fMLP and GM-CSF, and plasma membrane expression of flavocytochrome b558 and specific granule markers were assessed by fluorescence-activated cell sorting analysis. Protein levels of the flavocytochrome b558 subunits gp91phox and p22phox in whole neutrophil lysates were detected by Western blotting. RESULTS Stimulation of neutrophils with GM-CSF and fMLP increased the flavocytochrome b558 plasma membrane expression. The fMLP-induced translocation of flavocytochrome b558 was reduced in neutrophils from MDS patients (140%+/-9% vs 180%+/-13%, p<0.05). Analysis of cell surface expression of markers of flavocytochrome b558 containing granules (CD35 and CD66b) indicated that exocytosis of these granules in response to fMLP stimulation was not affected in MDS patients. Western blot analysis demonstrated a decreased protein expression level of the flavocytochrome b558 subunits gp91phox and p22phox in neutrophils from MDS patients. CONCLUSION Our results indicate both a lower basal protein level and a disturbed fMLP-induced increase in plasma membrane expression of flavocytochrome b558 in neutrophils from MDS patients, which together might play a role in decreased ROS production.
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Heijink IH, Kauffman HF, Postma DS, de Monchy JGR, Vellenga E. Sensitivity of IL-5 production to the cAMP-dependent pathway in human T cells is reduced by exogenous IL-2 in a phosphoinositide 3-kinase-dependent way. Eur J Immunol 2003; 33:2206-15. [PMID: 12884295 DOI: 10.1002/eji.200323804] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The cAMP-dependent pathway plays an important role in the regulation of T cell-mediated immune responses by inhibition of T cell proliferation, activation and production of Th1-like cytokines. Depending on costimulatory signals and on the activation status of T cells, cAMP also regulates the production of Th2-like cytokines, yet the mechanism is not completely defined. We investigated the effect of costimulation with IL-2 on cAMP-mediated inhibition of IL-5 secretion and the signaling pathways involved in these effects in freshly isolated, alpha-CD3/alpha-CD28-stimulated human T lymphocytes. We demonstrate that IL-2 counteracts the cAMP-mediated inhibitory effects on IL-5 secretion by the modulation of phosphoinositide 3-kinase (PI3-K)-dependent signaling. Our results indicate that phosphorylation of cAMP-responsive element-binding protein (CREB) and the activity of the small GTPase Rap1 are unlikely involved in the protective effect of IL-2. Instead, the effect of IL-2 may be mediated by the PI3-K-dependent inactivation of the forkhead-related transcription factor FKHR-L1, down-regulation of p27(kip) and abrogation of the cAMP-mediated inhibition of activator protein (AP)-1 binding activity. Together, our results indicate that increased IL-2-dependent PI3-K signaling leads to impaired negative feedback control of the production of Th2-type cytokine IL-5 by the cAMP-dependent pathway.
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213
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Spierings DCJ, de Vries EGE, Vellenga E, de Jong S. Loss of drug-induced activation of the CD95 apoptotic pathway in a cisplatin-resistant testicular germ cell tumor cell line. Cell Death Differ 2003; 10:808-22. [PMID: 12815464 DOI: 10.1038/sj.cdd.4401248] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Testicular germ cell tumors (TGCTs) are unusually sensitive to cisplatin. In the present study the role of the CD95 death pathway in cisplatin sensitivity of TGCT cells was studied in Tera and its in vitro acquired cisplatin-resistant subclone Tera-CP. Cisplatin induced an increase in CD95 membrane expression, which preceded the onset of apoptosis. Cisplatin-induced apoptosis was efficiently blocked by caspase-8 inhibitor zIETD-fmk in Tera cells, but only partially in Tera-CP cells. In addition, cisplatin induced FADD and caspase-8 recruitment to the CD95 receptor in Tera cells, which was not noticed in Tera-CP cells. Moreover, overexpression of vFLIP reduced apoptosis induction by cisplatin in Tera cells. CD95L-blocking experiments revealed the involvement of CD95/CD95L interactions in cisplatin-induced apoptosis of Tera cells as well as cisplatin-sensitive 833KE TGCT cells. Tera and 833KE cells, treated with low doses of cisplatin, were sensitive for an apoptosis-inducing anti-CD95 antibody. In contrast, CD95L blocking had no effect on cisplatin-induced apoptosis in Tera-CP or Scha, an intrinsic resistant TGCT cell line, nor did anti-CD95 antibody induce additional apoptosis in cisplatin-treated Tera-CP or Scha cells. Taken together, these results show that (1) cisplatin sensitivity of TGCT cells is dependent on the activation of the CD95 death pathway and (2) loss of cisplatin-induced activation of this CD95 signaling pathway may result in resistance to cisplatin.
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214
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Oude Nijhuis CSM, Vellenga E, Daenen SMGJ, Kamps WA, De Bont ESJM. Endothelial cells are main producers of interleukin 8 through Toll-like receptor 2 and 4 signaling during bacterial infection in leukopenic cancer patients. CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY 2003; 10:558-63. [PMID: 12853386 PMCID: PMC164273 DOI: 10.1128/cdli.10.4.558-563.2003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cancer patients who are leukopenic due to chemotherapy are susceptible to bacterial infections. Normally, clinical conditions during bacterial infections are caused by pathogen-associated molecular patterns, which are components that bind to Toll-like receptor (TLR) 2 (TLR-2) and TLR-4 on leukocytes, resulting in the production of inflammatory cytokines. The mechanism of this inflammatory response in cancer patients with diminished numbers of leukocytes is not completely clear. The levels of interleukin 1 beta (IL-1 beta) and tumor necrosis factor alpha measured in the circulation of leukopenic cancer patients are lower than those measured in that of nonleukopenic patients during bacterial infections, whereas plasma interleukin 8 (IL-8) levels show distinct identical increases during bacterial infections in both leukopenic and nonleukopenic patients. Normally, these cytokines are mainly secreted by leukocytes. In cancer patients with bacterial infections and a diminished number of leukocytes, other sources of IL-8 production, such as endothelial cells, might be expected. Endothelial cells instead of leukocytes become the most important producers of IL-8 during bacterial infections in patients with chemotherapy-induced leukopenia through TLR-2 and TLR-4 signaling. Whole blood samples from six cancer patients were stimulated with lipopolysaccharide (LPS), and then IL-8 concentrations in supernatants were measured. Further, human umbilical vein endothelial cells (HUVECs) were incubated with sera from leukopenic cancer patients with or without bacterial infections, and then IL-8 concentrations in supernatants were measured (n = 6). In addition, the same HUVEC experiment was performed with the addition of neutralizing antibodies against TLR-2 and TLR-4. During leukopenia (<10(9) cells/liter), LPS stimulation of whole blood did not result in an increase in IL-8 levels. However, when endothelial cells were incubated with sera from leukopenic cancer patients during bacterial infections, a three- to eightfold increase in IL-8 production was found, compared to the IL-8 production found after incubation with sera from patients without signs of infections. This increase did not reflect a higher level of IL-8 already present in the sera. Further, we demonstrated that IL-8 production induced in endothelial cells by sera from patients with documented gram-negative infections could be reduced significantly by up to 40% when the cells were incubated with neutralizing antibodies against TLR-4 (P = 0.028). The addition of TLR-2 antibodies slightly enhanced the reduction of IL-8 production. These results suggest that during bacterial infections in cancer patients with markedly diminished numbers of leukocytes, endothelial cells become important producers of IL-8 through TLR-4 signaling and, to a lesser extent, TLR-2 signaling.
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215
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Spierings DCJ, de Vries EGE, Vellenga E, de Jong S. The attractive Achilles heel of germ cell tumours: an inherent sensitivity to apoptosis-inducing stimuli. J Pathol 2003; 200:137-48. [PMID: 12754734 DOI: 10.1002/path.1373] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Testicular germ cell tumours (TGCTs) are extremely sensitive to cisplatin-containing chemotherapy. The rapid time course of apoptosis induction after exposure to cisplatin suggests that TGCT cells are primed to undergo programmed cell death as an inherent property of the cell of origin. In fact, apoptosis induction of germ cells in the testis is an important physiological mechanism to control the quality and quantity of the gametes produced. Although p53 protein is highly expressed in the majority of TGCTs, almost no p53 mutations have been detected. Interestingly, p53 overexpression is associated with loss of p21 and gain of mdm2 expression, which might indicate a partial loss in functionality of the p53 regulatory pathway in TGCTs. Besides p21, TGCTs often show low expression of other proteins involved in the regulation of cell cycle progression, such as the retinoblastoma protein and members of the INK4 family. It can be postulated that the deregulated G(1)-S phase checkpoint results in premature entry into the S phase upon DNA damage. In addition to Bcl-2 family members that are involved in the regulation of germ cell apoptosis in the normal testis via the mitochondrial death pathway, the Fas death pathway is also known to regulate apoptosis of germ cells in the testis. Since chemotherapy has been shown to activate the Fas death pathway and TGCTs co-express both Fas and its ligand FasL, TGCT cells might undergo apoptosis upon cisplatin treatment via autocrine or paracrine activation of the Fas system by FasL. The hypothesis suggested here is that the lack of cell cycle arrest following a cisplatin-containing treatment, together with the activation of the Fas death pathway and the mitochondrial death pathway, explains the rapid and efficient apoptosis of TGCT cells. Defining the mechanisms involved in the cisplatin sensitivity of TGCTs will provide tools to increase cisplatin sensitivity in other human tumours with acquired or intrinsic resistance.
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Boer AK, Drayer AL, Vellenga E. Stem cell factor enhances erythropoietin-mediated transactivation of signal transducer and activator of transcription 5 (STAT5) via the PKA/CREB pathway. Exp Hematol 2003; 31:512-20. [PMID: 12829027 DOI: 10.1016/s0301-472x(03)00075-4] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
OBJECTIVE To define whether the observed synergistic effects of erythropoietin (EPO) and stem cell factor (SCF) on erythroid cells can, in part, be mediated by the signal transducer and activator of transcription 5 (STAT5). METHODS STAT5 activation was examined in erythroid cell lines by analyzing the effects of EPO and SCF on STAT5 tyrosine phosphorylation, serine phosphorylation, DNA binding, and STAT5-mediated gene transactivation. RESULTS EPO induced a 5.0-fold+/-0.4-fold increase in STAT5 transactivation, which could be further enhanced by SCF. SCF pretreatment followed by EPO stimulation resulted in a 9.0-fold+/-0.9-fold increase in STAT5 transactivation, while SCF alone did not increase STAT5 transactivation. This costimulatory effect of SCF was not mediated by increased STAT5 tyrosine or serine phosphorylation or increased STAT5 DNA binding. In addition, enhanced STAT5 transactivation was independent of the phosphatidyl inositol 3-kinase and MAPK(p42/p44) pathways. Instead, the protein kinase A (PKA) inhibitor protein PKI and the PKA inhibitor H89 prevented the costimulatory SCF effect. Furthermore, the PKA target CREB showed a strongly increased and prolonged serine-133 phosphorylation after costimulation with SCF + EPO. The involvement of CREB in STAT5 transactivation was demonstrated by overexpression of serine-133-mutated CREB, which completely blocked the SCF effect. In addition, the CREB-binding protein CBP/p300 was shown to be essential for EPO- and SCF-mediated STAT5 transactivation. CONCLUSION SCF enhances the EPO-mediated STAT5 transactivation by triggering a PKA/CREB-dependent pathway.
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217
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Noach EJK, Ausema A, van Os R, Akkerman I, Koopal S, Weersing E, Dontje B, Vellenga E, de Haan G. Chemotherapy prior to autologous bone marrow transplantation impairs long-term engraftment in mice. Exp Hematol 2003; 31:528-34. [PMID: 12829029 DOI: 10.1016/s0301-472x(03)00068-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVE Autologous bone marrow transplantation in cancer patients is often preceded by multiple cycles of chemotherapy. In this study, we assessed in a mouse model whether stem cells were affected by prior chemotherapy. METHODS Donor mice were treated with three consecutive injections of 150 mg/kg 5-fluorouracil (5-FU). Peripheral blood counts were allowed to recover before the subsequent dose of 5-FU was given. Mice recovered from three doses of 5-FU and showed normal steady-state hematopoiesis. Bone marrow cells from these mice were mixed with congenic competitor cells and transplanted into lethally irradiated recipients. RESULTS Although in vivo homing of cells from these mice was not impaired, donor leukocyte contribution steadily decreased posttransplantation. In contrast to in vivo homing, both in vitro migration toward stromal-derived factor (SDF)-1 and the average CXC chemokine receptor-4 (CXCR4) expression were lower in 5-FU-treated cells. Moderate reductions in L-selectin and CD11a expression were observed on stem cells of 5-FU-treated mice. CD43, CD44, CD49d, and CD49e were normally expressed and could thus not explain the reduced engraftment of these cells. CONCLUSION We therefore conclude that 5-FU either directly damages stem cells or that the replicative stress induced by 5-FU causes a decline in stem cell reconstitution potential resulting in lower chimerism levels posttransplantation, that declines in time.
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218
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Wierenga PK, Setroikromo R, Kamps G, Kampinga HH, Vellenga E. Differences in heat sensitivity between normal and acute myeloid leukemic stem cells: feasibility of hyperthermic purging of leukemic cells from autologous stem cell grafts. Exp Hematol 2003; 31:421-7. [PMID: 12763141 DOI: 10.1016/s0301-472x(03)00049-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
OBJECTIVES In autologous stem cell transplantation contamination of the graft with malignant cells is frequently noticed and necessitates the use of in vivo or in vitro purging modalities. The hematopoietic recovery after transplantation depends on the number of stem and progenitor cells in the transplant. Therefore, in the present study the effects of hyperthermic treatment on the human normal and acute myeloid leukemic (AML) stem cell compartment were investigated. METHODS Normal bone marrow and AML blasts were heat treated up to 120 minutes at 43 degrees C. The surviving fractions of the different stem cell subsets were determined using in vitro methylcellulose and cobblestone area-forming cell (CAFC) clonogenic assays, as well as the in vivo NOD/SCID repopulating assay. The leukemic nature of the colonies from AML cells was confirmed by RT-PCR analysis. In order to increase the therapeutic index of the hyperthermic purging modality, the heat treatment was preceded by a 3-hour incubation at 37 degrees C with the ether lipid ET-18-OCH(3) (25 microg/mL). RESULTS It could be demonstrated that normal progenitor cells are far more resistant to hyperthermia than leukemic progenitor cells (56%+/-7% vs 9.9%+/-2.6% survival after 60 minutes at 43 degrees C, respectively). Furthermore, normal hematopoietic stem cells appear to be extremely resistant to the heat treatment (94%+/-9% survival after 60 minutes at 43 degrees C). In contrast, in the leukemic stem cell compartment no significant differences in heat sensitivity between the stem cells and progenitor subsets could be observed (12.3%+/-2.9% vs 9.9%+/-2.6% survival after 60 minutes at 43 degrees C, respectively). The combined treatment resulted in a survival for normal progenitor and stem cells of 32%+/-6% and 85%+/-15% after 60 minutes at 43 degrees C, respectively. Under these conditions the number of leukemic stem cells was reduced to 1%+/-0.3%. After 120 minutes at 43 degrees C, no AML-colonies could be detected anymore. CONCLUSIONS Our data demonstrate that leukemic stem cells have an increased hyperthermic sensitivity compared to their normal counterparts and that this difference can be further increased in combination with ET-18-OCH(3). These striking differences in heat sensitivity warrant the use of hyperthermia as a clinically applicable purging modality in autologous stem cell transplantation.
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219
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Wierenga ATJ, Vogelzang I, Eggen BJL, Vellenga E. Erythropoietin-induced serine 727 phosphorylation of STAT3 in erythroid cells is mediated by a MEK-, ERK-, and MSK1-dependent pathway. Exp Hematol 2003; 31:398-405. [PMID: 12763138 DOI: 10.1016/s0301-472x(03)00045-6] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
OBJECTIVE Erythropoietin (EPO) is a key regulator of erythropoiesis, playing a role in both the proliferation and differentiation of erythroid cells. One of the signal transduction molecules activated upon EPO stimulation is signal transducer and activator of transcription (STAT) 3. Besides tyrosine 705 phosphorylation of STAT3, serine 727 phosphorylation has been described upon EPO stimulation. In the present study, we investigated which molecular pathways mediate the STAT3 serine 727 phosphorylation and the functional implications of this phosphorylation. METHODS The EPO-dependent erythroid cell line ASE2 was used to investigate which signaling routes were involved in the STAT3 serine 727 phosphorylation. Western blotting using phosphospecific antibodies was used to assess the phosphorylation status of STAT3 molecules. Transfection analysis was performed to investigate the transactivational potential of STAT3, and quantitative RT-PCR was used to study the in vivo gene expression of STAT3-responsive genes. RESULTS Western blotting of extracts of cells exposed to various chemical inhibitors revealed that the MEK inhibitors PD98059 and U0126 abrogated the EPO-mediated STAT3 serine 727 phosphorylation without an effect on tyrosine phosphorylation. Further analysis showed that MSK1 is activated downstream of ERK, and retroviral transductions with kinase-inactive MSK1 revealed that MSK1 is necessary for STAT3 serine phosphorylation. Furthermore, the STAT3-mediated transactivation was reduced by blocking the STAT3 serine phosphorylation with the MEK inhibitor U0126 or by expression of kinase-inactive MSK1. CONCLUSIONS The EPO-induced STAT3 serine 727 phosphorylation is mediated by a pathway involving MEK, ERK, and MSK1. Furthermore, serine phosphorylation of STAT3 augments the transactivational potential of STAT3.
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Guikema JEJ, Hovenga S, Vellenga E, Conradie JJ, Abdulahad WH, Bekkema R, Smit JW, Zhan F, Shaughnessy J, Bos NA. CD27 is heterogeneously expressed in multiple myeloma: low CD27 expression in patients with high-risk disease. Br J Haematol 2003; 121:36-43. [PMID: 12670329 DOI: 10.1046/j.1365-2141.2003.04260.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Expression of CD27 on malignant plasma cells (PC) (CD138+CD38++) was analysed in a cross-sectional study of bone marrow (BM) samples from multiple myeloma (MM) patients (n = 28), monoclonal gammopathy of undetermined significance (MGUS) patients (n = 6) and BM PC from healthy donors (n = 4). MM PC expressed CD27 with a variable, lower intensity pattern compared with the consistent high expression in MGUS and healthy donors. MM patients in complete clinical remission displayed a higher percentage of CD27+ PC compared with patients at diagnosis, relapse or in partial remission. In MM, loss of CD27 correlated with loss of CD19 (R2 = 0.4, P < 0.0001). Human MM cell lines (n = 9) did not express CD27 whereas de novo plasma cell leukaemia (PCL) (n = 3) had a high expression. Re-analysis of a cDNA microarray data set, generated from newly diagnosed MM patients (n = 74), demonstrated that the MM subgroup with the highest prevalence of poor prognostic factors had the lowest CD27 mRNA expression. Fluorescence-activated cell sorting and allele-specific oligonucleotide polymerase chain reaction showed that both CD27+ and CD27- PC subpopulations in MM can belong to the clonal disorder. In conclusion, CD27 is heterogeneously expressed on MM PC and loss of CD27 expression might have prognostic value in MM.
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221
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Heijink IH, Vellenga E, Borger P, Postma DS, Monchy JGRD, Kauffman HF. Polarized Th1 and Th2 cells are less responsive to negative feedback by receptors coupled to the AC/cAMP system compared to freshly isolated T cells. Br J Pharmacol 2003; 138:1441-50. [PMID: 12721099 PMCID: PMC1573801 DOI: 10.1038/sj.bjp.0705193] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. The adenylyl cyclase (AC)/cyclic adenosine monophosphate (cAMP) system is known to negatively regulate transcriptional activity of T cells, thereby possibly modulating T-cell-mediated responses at the sites of inflammation. Effects of cAMP have been widely studied in freshly isolated T cells and T-cell clones; yet, effects in differentiated Th1 and Th2 cells are largely unknown. 2. To obtain differentiated T helper cells, we activated naive T cells for 1 week in the presence of IL-12 plus alpha-IL-4 to generate Th1-type cells and in the presence of IL-4 plus alpha-IL-12 to generate Th2-type cells. 3. We demonstrate that, in contrast to freshly isolated T cells, the production of Th1 (IFN-gamma) and Th2 (IL-4, IL-5) cytokines in polarized T helper cells is not strictly controlled by the activation of AC/cAMP-linked beta(2)-adrenergic and prostaglandin (PG)E(2) receptors. 4. In Th2 cells, PGE(2) could still activate the G(s) protein-coupled AC/cAMP system and subsequently induce CREB phosphorylation, whereas PGE(2) was unable to activate the cAMP-dependent pathway in Th1 cells. In both Th1 and Th2 cells, the induction of CREB phosphorylation by beta(2)-agonist fenoterol was impaired. 5. The loss of control over cytokine production by cAMP elevating agents in differentiated Th1 and Th2 subsets may have important implications for the regulation of Th1- and Th2-mediated diseases, in particular those associated with the ongoing immune responses.
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Segeren CM, Sonneveld P, van der Holt B, Vellenga E, Croockewit AJ, Verhoef GEG, Cornelissen JJ, Schaafsma MR, van Oers MHJ, Wijermans PW, Fibbe WE, Wittebol S, Schouten HC, van Marwijk Kooy M, Biesma DH, Baars JW, Slater R, Steijaert MMC, Buijt I, Lokhorst HM. Overall and event-free survival are not improved by the use of myeloablative therapy following intensified chemotherapy in previously untreated patients with multiple myeloma: a prospective randomized phase 3 study. Blood 2003; 101:2144-51. [PMID: 12456509 DOI: 10.1182/blood-2002-03-0889] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We compared the efficacy of intensified chemotherapy followed by myeloablative therapy and autologous stem cell rescue with intensified chemotherapy alone in patients newly diagnosed with multiple myeloma. There were 261 eligible patients younger than 66 years with stage II/III multiple myeloma who were randomized after remission induction therapy with vincristine, adriamycin, dexamethasone (VAD) to receive intensified chemotherapy, that is, melphalan 140 mg/m(2) administered intravenously in 2 doses of 70 mg/m(2) (intermediate-dose melphalan [IDM]) without stem cell rescue (n = 129) or the same regimen followed by myeloablative therapy consisting of cyclophosphamide, total body irradiation, and autologous stem cell reinfusion (n = 132). Interferon-alpha-2a was given as maintenance. Of the eligible patients, 79% received both cycles of IDM and 79% of allocated patients actually received myeloablative treatment. The response rate (complete remission [CR] plus partial remission [PR]) was 88% in the intensified chemotherapy group versus 95% in the myeloablative treatment group. CR was significantly higher after myeloablative therapy (13% versus 29%; P =.002). With a median follow-up of 33 months (range, 8-65 months), the event-free survival (EFS) was not different between the treatments (median 21 months versus 22 months; P =.28). Time to progression (TTP) was significantly longer after myeloablative treatment (25 months versus 31 months; P =.04). The overall survival (OS) was not different (50 months versus 47 months; P =.41). Intensified chemotherapy followed by myeloablative therapy as first-line treatment for multiple myeloma resulted in a higher CR and a longer TTP when compared with intensified chemotherapy alone. However, it did not result in a better EFS and OS.
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223
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de Haan G, Weersing E, Dontje B, van Os R, Bystrykh LV, Vellenga E, Miller G. In vitro generation of long-term repopulating hematopoietic stem cells by fibroblast growth factor-1. Dev Cell 2003; 4:241-51. [PMID: 12586067 DOI: 10.1016/s1534-5807(03)00018-2] [Citation(s) in RCA: 129] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The role of fibroblast growth factors and their receptors (FGFRs) in the regulation of normal hematopoietic stem cells is unknown. Here we show that, in mouse bone marrow, long-term repopulating stem cells are found exclusively in the FGFR(+) cell fraction. During differentiation toward committed progenitors, stem cells show loss of FGFR expression. Prolonged culture of bone marrow cells in serum-free medium supplemented with only FGF-1 resulted in robust expansion of multilineage, serially transplantable, long-term repopulating hematopoietic stem cells. Thus, we have identified a simple method of generating large numbers of rapidly engrafting stem cells that have not been genetically manipulated. Our results show that the multipotential properties of stem cells are dependent on signaling through FGF receptors and that FGF-1 plays an important role in hematopoietic stem cell homeostasis.
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Fuhler GM, Drayer AL, Vellenga E. Decreased phosphorylation of protein kinase B and extracellular signal-regulated kinase in neutrophils from patients with myelodysplasia. Blood 2003; 101:1172-80. [PMID: 12529294 DOI: 10.1182/blood.v101.3.1172] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Neutrophils from patients with myelodysplastic syndrome (MDS) show a disturbed differentiation pattern and are generally dysfunctional. To study these defects in more detail, we investigated reactive-oxygen species (ROS) production and F-actin polymerization in neutrophils from MDS patients and healthy controls and the involvement of N-formyl-L-methionyl-L-lucyl-L-phenylaline (fMLP) and granulocyte macrophage-colony-stimulating factor (GM-CSF)-stimulated signal transduction pathways. Following fMLP stimulation, similar levels of respiratory burst, F-actin polymerization, and activation of the small GTPase Rac2 were demonstrated in MDS and normal neutrophils. However, GM-CSF and G-CSF priming of ROS production were significantly decreased in MDS patients. We subsequently investigated the signal transduction pathways involved in ROS generation and demonstrated that fMLP-stimulated ROS production was inhibited by the phosphatidylinositol 3 kinase (PI3K) inhibitor LY294002, but not by the MAPK/ERK kinase (MEK) inhibitor U0126. In contrast, ROS production induced by fMLP stimulation of GM-CSF-primed cells was inhibited by LY294002 and U0126. This coincides with enhanced protein kinase B (PKB/Akt) phosphorylation that was PI3K dependent and enhanced extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) phosphorylation that was PI3K independent. We demonstrated higher protein levels of the PI3K subunit p110 in neutrophils from MDS patients and found that though the fMLP-induced phosphorylation of PKB/Akt and ERK1/2 could also be enhanced by pretreatment with GM-CSF in these patients, the degree and kinetics of PKB/Akt and ERK1/2 phosphorylation were significantly disturbed. These defects were observed despite a normal GM-CSF-induced signal transducer and activator of transcription 5 (STAT5) phosphorylation. Our results indicate that the reduced priming of neutrophil ROS production in MDS patients might be caused by a disturbed convergence of the fMLP and GM-CSF signaling routes.
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Plasschaert SLA, Vellenga E, de Bont ESJM, van der Kolk DM, Veerman AJP, Sluiter WJ, Daenen SMG, de Vries EGE, Kamps WA. High functional P-glycoprotein activity is more often present in T-cell acute lymphoblastic leukaemic cells in adults than in children. Leuk Lymphoma 2003; 44:85-95. [PMID: 12691146 DOI: 10.1080/1042819021000040288] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
There is a distinct difference in prognosis between childhood versus adult acute lymphoblastic leukaemia (ALL). To define whether multidrug resistance (MDR) genes might contribute to this distinction, the expression and functional activity of P-glycoprotein (P-gp) and MDR associated proteins (MRP) were determined with RT-PCR (MDR-1, MRP1, MRP2, MRP3) and flow cytometry (P-gp and MRP). Patient samples were obtained from 36 children and 35 adults with de novo ALL. Of these patients, 38 showed a T-lineage and 33 showed a B-lineage immunophenotype. In the samples, large variability in P-gp activity (0.8-4.9) and MRP activity (1.1-13.9) was observed. Most T-ALL patients with high P-gp activity were adults (89%). The mRNA expression of MDR-1 correlated weakly with P-gp activity. In contrast, MRP activity did not correlate with the mRNA expression of MRP1, MRP2 and MRP3. In T-ALL, a worse overall survival and event-free survival was observed with increasing P-gp activity. P-gp activity had no prognostic impact in B-lineage ALL. In addition, high MRP activity did not influence treatment outcome in either T- or B-lineage ALL. Multivariate Cox regression analysis, showed P-gp activity to be the only unfavourable prognostic factor for overall survival in T-ALL. In conclusion, this study demonstrates the prognostic relevance of P-gp activity in T-ALL. Since the majority of the patients with high P-gp activity were adults, P-gp might contribute to the poor prognosis of adult T-ALL.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/genetics
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Adolescent
- Adult
- Age Factors
- Aged
- Child
- Child, Preschool
- Female
- Humans
- Leukemia, B-Cell/diagnosis
- Leukemia, B-Cell/genetics
- Leukemia, B-Cell/mortality
- Leukemia, T-Cell/diagnosis
- Leukemia, T-Cell/genetics
- Leukemia, T-Cell/mortality
- Male
- Membrane Transport Proteins
- Middle Aged
- Multidrug Resistance-Associated Protein 2
- Multidrug Resistance-Associated Proteins/genetics
- Multidrug Resistance-Associated Proteins/metabolism
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/diagnosis
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/genetics
- Precursor Cell Lymphoblastic Leukemia-Lymphoma/mortality
- Prognosis
- RNA, Messenger/analysis
- Regression Analysis
- Reverse Transcriptase Polymerase Chain Reaction
- Survival Analysis
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