Limited numbers of apoptotic cells in fresh paraffin embedded bone marrow samples of patients with myelodysplastic syndrome.

In myelodysplasia (MDS) the precise mechanism of ineffective erythropoiesis is not fully elucidated, but it is suggested that apoptosis may contribute to this process. We performed TdT-mediated dUTP-nick end labelling (TUNEL) staining of paraffin embedded bone marrow specimens to assess the amount of apoptotic cells in 21 MDS patients (7 RA, 3 RARS, 5 RAEB, 3 RAEB-T, 3 CMML) and five normal controls. In 10 MDS patients the TUNEL assay was performed in combination with immunostaining for Glycophorin-A (GpA) to determine apoptosis in the maturing erythroid compartment.

Breast cancer resistance protein (BCRP) in acute leukemia.

Multidrug resistance, cross-resistance to structurally and functionally unrelated drugs, is an important cause of treatment failure in acute leukemia. Multidrug resistance can result from the overexpression of ATP-dependent efflux pumps, such as P-glycoprotein and members of the multidrug resistance associated protein (MRP) family. Recently a novel transporter has been identified, which is called breast cancer resistance protein (BCRP), ABCG2 or mitoxantrone resistance protein.

The possible role of matrix metalloproteinase (MMP)-2 and MMP-9 in cancer, e.g. acute leukemia.

In the past decades, a lot of effort has been put in identifying the role of matrix metalloproteinases (MMPs) in cancer. The main role of MMPs in angiogenesis, tumor growth and metastasis is degradation of extracellular matrix (ECM) and release and/or activation of growth factors through their degradative activity. The degradative activity finally results in cancer progression.

Tissue distribution of the death ligand TRAIL and its receptors.

Recombinant human (rh) TNF-related apoptosis-inducing ligand (TRAIL) harbors potential as an anticancer agent. RhTRAIL induces apoptosis via the TRAIL receptors TRAIL-R1 and TRAIL-R2 in tumors and is non-toxic to nonhuman primates. Because limited data are available about TRAIL receptor distribution, we performed an immunohistochemical (IHC) analysis of the expression of TRAIL-R1, TRAIL-R2, the anti-apoptotic TRAIL receptor TRAIL-R3, and TRAIL in normal human and chimpanzee tissues.

Low p21Waf1/Cip1 protein level sensitizes testicular germ cell tumor cells to Fas-mediated apoptosis.

In the present study, we investigated the relation between p21 expression and the sensitivity of testicular germ cell tumor (TGCT) cells to apoptotic stimuli. Despite similar cisplatin-induced wild-type p53 accumulation, the TGCT cell lines Tera and Scha expressed low p21 protein and mRNA levels in comparison to A2780 ovarian cancer cells. Inhibition of the proteasome complex with MG-132 increased p21 protein levels in TGCT cells but much more in A2780 cells, whereas cisplatin had no additional effect on p21 protein levels.

Factors influencing haematological recovery following high-dose chemotherapy and peripheral stem-cell transplantation for haematological malignancies; 1-year analysis.

Peripheral blood counts and factors influencing haematological recovery in 98 patients with a relapse-free survival of > or =1 year treated with high-dose chemotherapy (HDC) and peripheral stem-cell transplantation (PSCT) for haematological malignancies were analysed. One year after PSCT full haematological recovery was demonstrated for haemoglobin (Hb) in 47% of patients, for the white blood cell count (WBC) in 94%, and for platelets in 64%; 39% had a trilineage recovery. In the multivariate analysis, recovery was influenced by age (P=0.

Disturbed granulocyte macrophage-colony stimulating factor priming of phosphatidylinositol 3,4,5-trisphosphate accumulation and Rac activation in fMLP-stimulated neutrophils from patients with myelodysplasia.

The production of reactive oxygen species (ROS) by human neutrophils is imperative for their bactericidal activity. Proinflammatory agents such as granulocyte macrophage-colony stimulating factor (GM-CSF) can prime ROS production in response to chemoattractants such as N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP). In neutrophils from patients suffering from Myelodysplastic syndromes (MDS), a clonal, hematological disorder characterized by recurrent bacterial infections, this GM-CSF priming is severely impaired.

Prognosis in childhood and adult acute lymphoblastic leukaemia: a question of maturation?

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.

cAMP/PKA-mediated regulation of erythropoiesis.

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.

CD27-triggering on primary plasma cell leukaemia cells has anti-apoptotic effects involving mitogen activated protein kinases.

Primary plasma cell leukaemia (PCL) is a rare plasma cell malignancy, which is related to multiple myeloma (MM) and is characterized by a poor prognosis. In a previous study we demonstrated that PCL plasma cells display a high expression of CD27, in contrast to MM plasma cells. The present study was set out to assess the functional properties of CD27 expressed on PCL plasma cells by triggering with its ligand CD70.

The role of breast cancer resistance protein in acute lymphoblastic leukemia.

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.

Routine radiography does not have a role in the diagnostic evaluation of ambulatory adult febrile neutropenic cancer patients.

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.

Constitutive NF-kappaB DNA-binding activity in AML is frequently mediated by a Ras/PI3-K/PKB-dependent pathway.

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.

Lipopolysaccharide-binding protein: a possible diagnostic marker for Gram-negative bacteremia in neutropenic cancer patients.

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.

Predictive value of early 18F-fluoro-deoxyglucose positron emission tomography in chemosensitive relapsed lymphoma.

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.

RFP2, c13ORF1, and FAM10A4 are the most likely tumor suppressor gene candidates for B-cell chronic lymphocytic leukemia.

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.

Ultrastructural study shows morphologic features of apoptosis and para-apoptosis in megakaryocytes from patients with idiopathic thrombocytopenic purpura.

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%).

Reduced expression of flavocytochrome b558, a component of the NADPH oxidase complex, in neutrophils from patients with myelodysplasia.

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.

Constitutive cytoplasmic localization of p21(Waf1/Cip1) affects the apoptotic process in monocytic leukaemia.

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.

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.

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.

Endothelial cells are main producers of interleukin 8 through Toll-like receptor 2 and 4 signaling during bacterial infection in leukopenic cancer patients.

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.

Chemotherapy prior to autologous bone marrow transplantation impairs long-term engraftment in mice.

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).

Stem cell factor enhances erythropoietin-mediated transactivation of signal transducer and activator of transcription 5 (STAT5) via the PKA/CREB pathway.

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.

Loss of drug-induced activation of the CD95 apoptotic pathway in a cisplatin-resistant testicular germ cell tumor cell line.

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.

Differences in heat sensitivity between normal and acute myeloid leukemic stem cells: feasibility of hyperthermic purging of leukemic cells from autologous stem cell grafts.

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.