Search results for "leukemia"

The Soluble Interleukin-6 Receptora

2006

NFATc1 Is Transcriptionally Activated in Chronic Lymphocytic Leukemia (CLL) By Promotor DNA-Hypomethylation Which Correlates with in-Vitro Vulnerabil…

2014

Abstract Chronic lymphocytic leukemia (CLL), the most frequent adult leukemia in Western countries, is characterized by progressive accumulation of mature, monoclonal B lymphocytes in blood, bone marrow, and lymphoid tissues. In the pathogenesis and treatment of CLL, B cell receptor (BCR) signaling plays a crucial role, and aberrations in downstream pathways that become activated in CLL need to be better defined. One downstream target of BCR signaling is NFATc1, a transcription factor with a high oncogenic and transforming potential. Employing a genome-wide comparative DNA methylation analysis the NFATc1 5’ region was identified to be DNA hypomethylated in CLL patient samples. The pilot ser…

Drivers of topoisomerase II poisoning mimic and complement cytotoxicity in AML cells

2019

Recently approved cancer drugs remain out-of-reach to most patients due to prohibitive costs and only few produce clinically meaningful benefits. An untapped alternative is to enhance the efficacy and safety of existing cancer drugs. We hypothesized that the response to topoisomerase II poisons, a very successful group of cancer drugs, can be improved by considering treatment-associated transcript levels. To this end, we analyzed transcriptomes from Acute Myeloid Leukemia (AML) cell lines treated with the topoisomerase II poison etoposide. Using complementary criteria of co-regulation within networks and of essentiality for cell survival, we identified and functionally confirmed 11 druggabl…

The CD38-Positive and CD38-Negative Subsets of CD34(high)-Positive Primary Acute Myeloid Leukemia Blasts Differ Considerably in the Expression of Imm…

2008

Abstract Acute myeloid leukemia (AML) is thought to arise from a rare putative ‘leukemic stem cell’ that is capable of self-renewal and formation of leukemic blasts. Serial xenotransplantation studies in immunodeficient mice have shown that this leukemia-initiating cell resides at very low numbers within CD34(high)-positive CD38-negative AML cells. Thus, immunotherapeutic approaches successfully eradicating this cell compartment should result in cure from disease. The objective of our study was to characterize the immune phenotype of the CD38-negative and CD38-positive subsets of primary CD34(high)-positive AML blasts ex vivo. We obtained therapeutic leukapheresis products from 17 AML patie…

Cytotoxicity of fagaramide derivative and canthin-6-one from Zanthoxylum (Rutaceae) species against multidrug resistant leukemia cells

2019

In our continuous search for cytotoxic compounds from the genus Zanthoxylum, chromatographic separation of the MeOH/CH2Cl2 (1:1) extract of Z. chalybeum yielded one new alkamide; 4-(isoprenyloxy)-3-methoxy-3,4-deoxymethylenedioxyfagaramide (1) and a known one; fagaramide (2). Similarly, from the MeOH/CH2Cl2 (1:1) extract of the stem bark of Z. parachanthum four known compounds; canthin-6-one (3), dihydrochelerythrine (4), lupeol (5) and sesamin (6) were isolated. Characterization of the structures of these compounds was achieved using spectroscopic techniques (NMR and MS). Using resazurin reduction assay 1, 3 and 6 displayed moderate cytotoxicity with IC50 values below 50 μM against the dru…

Soluble gp130 is the natural inhibitor of soluble interleukin-6 receptor transsignaling responses

2001

Signal transduction in response to interleukin-6 (IL-6) requires binding of the cytokine to its receptor (IL-6R) and subsequent homodimerization of the signal transducer gp130. The complex of IL-6 and soluble IL-6R (sIL-6R) triggers dimerization of gp130 and induces responses on cells that do not express membrane bound IL-6R. Naturally occurring soluble gp130 (sgp130) can be found in a ternary complex with IL-6 and sIL-6R. We created recombinant sgp130 proteins that showed binding to IL-6 in complex with sIL-6R and inhibited IL-6/sIL-6R induced proliferation of BAF/3 cells expressing gp130. Surprisingly, sgp130 proteins did not affect IL-6 stimulated proliferation of BAF/3 cells expressing …

Mechanisms of Autocrine and Paracrine Growth Control in Acute Myelogenous Leukemia

1990

Blast cells of a high proportion of patients with acute myelogenous leukemia (AML) proliferate in response to exogenous hematopoetic growth factors, both in vitro [9, 14, 26, 36, 48, 65] and in vivo [20]. Whereas leukemic colony-forming cells (L-CFCs) from most patients share their growth factor dependence with normal committed myeloid progenitor cells (CFU-GMs), some AML samples autonomously form colonies in agar and are therefore believed to bypass growth factor requirements [17, 42, 72]. Autocrine growth factor production has been identified as one mechanism used by AML blasts to supply various growth-promoting molecules. Moreover nontransformed accessory bone marrow cells have been show…

Monitoring of FLT3 Phosphorylation and FLT3 Ligand Levels in Patients with FLT3-ITD Mutated Acute Myeloid Leukemia (AML) Treated with Midostaurin wit…

2018

Abstract Background: Target inhibition of FLT3 by therapy with the recently FDA- and EMA-approved multi-targeted tyrosine kinase inhibitor (TKI) midostaurin can be monitored by plasma inhibitor activity (PIA) analysis by visualizing the level of target-dephosphorylation as previously described. When combining intensive chemotherapy with midostaurin, we have recently shown that the TKI achieves the lowest level of FLT3 phosphorylation (p-FLT3) at the end of the 1st induction cycle, indicating a deep target inhibition. However, sufficient inhibition could not be maintained during subsequent cycles by midostaurin in combination with chemotherapy, but it was reestablished during maintenance the…

Gene Expression Profile of Chronic Myeloid Leukemia Innately Resistant to Imatinib

2007

Background. Most chronic myeloid leukemia patients who receive imatinib as first line-terapy will obtain, after 12 months treatment, complete cytogenetic and molecular response . However several cases will not achieve molecular response, but their innate mechanism(s) of resistance remain poorly understood. We tried to explore the molecular events involved in innate resistance in CML. Study design. Five patients who were molecular “non responder” and seven “major” responder were investigated by using the expression profile of a set of 380 genes. Multiple testing procedure (MTP), Significance Analysis of Microarrays (SAM), Empirical Bayes Analysis of Microarrays (EBAM), False Discovery Rate (…

Acute Myeloid Leukemia in Adults

2018

AML is a malignancy of hematopoietic immature precursors (myeloblasts) that accumulate in the BM at the expense of their normal counterparts.