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AML Cell Lines (aml + cell_line)

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Medical Sciences	100%

Selected Abstracts

A celecoxib derivative inhibits focal adhesion signaling and induces caspase-8-dependent apoptosis in human acute myeloid leukemia cells

INTERNATIONAL JOURNAL OF CANCER, Issue 1 2008
Isolda Casanova
Abstract Most acute myeloid leukemias (AMLs), including those with c-Kit or FLT3 mutations, show enhanced anchorage independent growth associated with constitutive activation of focal adhesion proteins. Moreover, these alterations increase cell survival, inhibit apoptosis and are associated with poor prognosis and resistance to chemotherapy. Therefore, the induction of apoptosis by selective inhibition of focal adhesion signaling may represent a novel anti-AML therapy. Here, we have evaluated the antitumor effect and the mechanism of action of celecoxib and E7123, a non-Cox-2 inhibitor derivative, in a panel of human AML cell lines and bone marrow mononuclear cells from AML patients. Both compounds induce cell death by inhibiting focal adhesion signaling through p130Cas, FAK and c-Src, leading to caspase-8 dependent apoptosis. This mechanism of action differs from that of classical cytotoxic drugs or of other targeted therapies, and is amenable to rational drug development. Therefore, both drugs could be developed as AML therapeutics; nevertheless, E7123 shows more activity than celecoxib against AML cells, and may not present its Cox-2 dependent cardiovascular toxicity. Finally, our results support the evaluation of celecoxib in AML patients, and the preclinical evaluation of E7123, before its possible clinical testing. © 2008 Wiley-Liss, Inc. [source]

The NF (Nuclear factor)-,B inhibitor parthenolide interacts with histone deacetylase inhibitors to induce MKK7/JNK1-dependent apoptosis in human acute myeloid leukaemia cells

BRITISH JOURNAL OF HAEMATOLOGY, Issue 1 2010
Yun Dai
Summary Interactions between the nuclear factor (NF)-,B inhibitor parthenolide and the pan-histone deacetylase inhibitors (HDACIs) vorinostat and LBH589 were investigated in human acute myeloid leukaemia (AML) cells, including primary AML blasts. Co-administration of parthenolide blocked HDACI-mediated phosphorylation/activation of IKK and RelA/p65 in association with increased JNK1 activation in various AML cell types. These events were accompanied by an increase in apoptosis in multiple AML cell lines (e.g. U937, HL-60, NB4, MV-4-11, and MOLM-13). Significantly, parthenolide also increased HDACI-mediated cell death in haematopoietic cells transduced with the MLL - MLLT1 fusion gene, which exhibit certain leukaemia-initiating cell characteristics, as well as primary AML blasts. Exposure to parthenolide/HDACI regimens clearly inhibited the growth of AML-colony-forming units but was relatively sparing toward normal haematopoietic progenitors. Notably, blockade of c-Jun N-terminal kinase (JNK) signalling by either pharmacological inhibitors or genetic means (e.g. dominant-negative JNK1 or JNK1 shRNA) diminished parthenolide/HDACI-mediated lethality. Moreover, dominant-negative MKK7, but not dominant-negative MKK4/SEK1, blocked JNK1 activation and apoptosis induced by parthenolide/HDACI regimens. Together, these findings indicate that parthenolide potentiates HDACI lethality in human AML cells through a process involving NF-,B inhibition and subsequent MKK7-dependent activation of the SAPK/JNK pathway. They also raise the possibility that this strategy may target leukaemic progenitor cells. [source]

Epigenetic inactivation of secreted Frizzled-related proteins in acute myeloid leukaemia

BRITISH JOURNAL OF HAEMATOLOGY, Issue 5 2008
E. Jost
Summary The Wnt signalling pathway has a key function in stem cell maintenance and differentiation of haematopoietic progenitors. Secreted Frizzled-related protein genes (SFRPs), functioning as Wnt signalling antagonists, have been found to be downregulated by promoter hypermethylation in many tumours. To analyse epigenetic dysregulation of SFRPs in acute myeloid leukaemia (AML), we examined the promoter methylation status of SFRP1, - 2, - 4 and - 5 in AML cell lines by methylation-specific polymerase chain reaction (MSP). Aberrant CpG island methylation was found for all four SFRP genes. By real-time reverse transcription-PCR, corresponding transcriptional silencing for SFRP1 and - 2 was demonstrated and treatment of cell lines with 5-aza -2,-deoxycytidine resulted in re-expression. The methylation status of the SFRP genes was analysed in 100 specimens obtained from AML patients at diagnosis. The frequencies of aberrant methylation among the patient samples were 29% for SFRP1, 19% for SFRP2, 0% for SFRP4 and 9% for SFRP5. For SFRP2, a correlation between promoter hypermethylation and transcriptional downregulation was found in primary AML samples. Among AML cases with a favourable karyotype, hypermethylation of SFRP genes was restricted to patients with core binding factor (CBF) leukaemia, and aberrant methylation of the SFRP2 promoter was an adverse risk factor for survival in CBF leukaemia. [source]

JTE-607, a multiple cytokine production inhibitor, induces apoptosis accompanied by an increase in p21waf1/cip1 in acute myelogenous leukemia cells

CANCER SCIENCE, Issue 3 2010
Nobuyuki Tajima
(Cancer Sci 2010; 101: 774,781) Proinflammatory cytokines and growth factors have been thought to play crucial roles in the pathology of acute myelogenous leukemia (AML) by supporting the proliferation and survival of AML cells in an autocrine and paracrine manner, although further elucidation is required. JTE-607 was originally identified as a multiple cytokine inhibitor that suppresses production of proinflammatory cytokines from lipopolysaccharide (LPS)-stimulated peripheral blood mononuclear cells. Herein, we report that JTE-607 exhibits inhibitory activity on the growth of AML cell lines accompanying reduction of the proinflammatory cytokine and growth factor production. In in vitro studies, JTE-607 suppressed expression and production of cytokines, which are spontaneously up-regulated in AML cell lines. JTE-607 also abrogated proliferation of AML cells in a concentration range in which colony formation of normal bone marrow cells was not affected. The growth inhibition by JTE-607 was characterized by induction of cell-cycle arrest at the S-phase and apoptosis, accompanied by a decrease in c-Myc and increase in p21waf1/cip1. In a leukemia model engrafted with U-937 cells, JTE-607 significantly prolonged survival in mice and reduced human cytokine mRNA levels in the bone marrow. These results suggest the usefulness of JTE-607 in therapeutic applications for patients with hypercytokinemia and aggressive AML cell proliferation. [source]