sulindac and Leukemia--Myeloid--Acute

Acute myeloid leukemia (AML) is a heterogeneous hematological malignancy. Treatment of patients suffering from high-risk AML as defined by clinical parameters, cytogenetics, and/or molecular analyses is often unsuccessful. OSI-461 is a pro-apoptotic compound that has been proposed as a novel therapeutic option for patients suffering from solid tumors like prostate or colorectal carcinoma. But little is known about its anti-proliferative potential in AML. Hence, we treated bone marrow derived CD34(+) selected blast cells from 20 AML patients and the five AML cell lines KG-1a, THP-1, HL-60, U-937, and MV4-11 with the physiologically achievable concentration of 1 μM OSI-461 or equal amounts of DMSO as a control. Following incubation with OSI-461, we found a consistent induction of apoptosis and an accumulation of cells in the G2/M phase of the cell cycle. In addition, we demonstrate that the OSI-461 mediated anti-proliferative effects observed in AML are associated with the induction of the pro-apoptotic cytokine mda-7/IL-24 and activation of the growth arrest and DNA-damage inducible genes (GADD) 45α and 45γ. Furthermore, OSI-461 treated leukemia cells did not regain their proliferative potential for up to 8 days after cessation of treatment following the initial 48 h treatment period with 1 μM OSI-461. This indicates sufficient targeting of the leukemia-initiating cells in our in vitro experiments through OSI-461. The AML samples tested in this study included samples from patients who were resistant to conventional chemotherapy and/or had FLT3-ITD mutations demonstrating the high potential of OSI-461 in human AML.

Topics: Apoptosis; Cell Cycle; Cell Line, Tumor; Clinical Trials as Topic; Gene Expression; Humans; Leukemia, Myeloid, Acute; Phosphodiesterase Inhibitors; Sulindac

Acute myeloid leukemia is a heterogeneous disease with varying genetic and molecular pathologies. Non-steroidal anti-inflammatory drugs (NSAIDs) have been proven to possess significant anti-proliferative potential in various cancer cells in vitro and in vivo. Hence, treatment with these agents can be utilized to study disease specific anti-proliferative pathways. In this study, a total number of 42 bone marrow derived CD34(+) selected de novo AML patient samples and the AML cell lines THP-1 and HL-60 were treated with the NSAIDs Sulindac sulfide and Diclofenac. We analyzed viability, apoptosis, differentiation and addressed the molecular mechanisms involved. We found a consistent induction of apoptosis and to some extent an increased myeloid differentiation capacity in NSAID treated AML cells. Comprehensive protein and gene expression profiling of Diclofenac treated AML cells revealed transcriptional activation of GADD45α and its downstream MAPK/JNK pathway as well as increased protein levels of the caspase-3 precursor. This pointed towards a role of the c-Jun NH(2)-terminal kinase (JNK) in NSAID mediated apoptosis that we found indeed to be dependent on JNK activity as addition of a specific JNK-inhibitor abrogated apoptosis. Furthermore, the AP-1 transcription factor family members' c-Jun, JunB and Fra-2 were transcriptionally activated in NSAID treated AML cells and re-expression of these transcription factors led to activation of GADD45α with induction of apoptosis. Mechanistically, we demonstrate that NSAIDs induce apoptosis in AML through a novel pathway involving increased expression of AP-1 heterodimers, which by itself is sufficient to induce GADD45α expression with consecutive activation of JNK and induction of apoptosis.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Apoptosis; Caspase 3; Cell Cycle Proteins; Cell Differentiation; Cell Survival; Cloning, Molecular; Diclofenac; Flow Cytometry; Fos-Related Antigen-2; Gene Expression Profiling; Gene Expression Regulation, Neoplastic; Genetic Vectors; HL-60 Cells; Humans; JNK Mitogen-Activated Protein Kinases; Leukemia, Myeloid, Acute; Nuclear Proteins; Proto-Oncogene Proteins c-jun; RNA Interference; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Sulindac; Transcription Factor AP-1; Transcriptional Activation

Chromosomal translocations can lead to the formation of chimeric genes encoding fusion proteins such as PML/RARα, PLZF/RARα, and AML-1/ETO, which are able to induce and maintain acute myeloid leukemia (AML). One key mechanism in leukemogenesis is increased self renewal of leukemic stem cells via aberrant activation of the Wnt signaling pathway. Either X-RAR, PML/RARα and PLZF/RARα or AML-1/ETO activate Wnt signaling by upregulating γ-catenin and β-catenin. In a prospective study, a lower risk of leukemia was observed with aspirin use, which is consistent with numerous studies reporting an inverse association of aspirin with other cancers. Furthermore, a reduction in leukemia risk was associated with use of non-steroidal anti-inflammatory drug (NSAID), where the effects on AML risk was FAB subtype-specific. To better investigate whether NSAID treatment is effective, we used Sulindac Sulfide in X-RARα-positive progenitor cell models. Sulindac Sulfide (SSi) is a derivative of Sulindac, a NSAID known to inactivate Wnt signaling. We found that SSi downregulated both β-catenin and γ-catenin in X-RARα-expressing cells and reversed the leukemic phenotype by reducing stem cell capacity and increasing differentiation potential in X-RARα-positive HSCs. The data presented herein show that SSi inhibits the leukemic cell growth as well as hematopoietic progenitors cells (HPCs) expressing PML/RARα, and it indicates that Sulindac is a valid molecular therapeutic approach that should be further validated using in vivo leukemia models and in clinical settings.

Topics: Animals; Apoptosis; beta Catenin; Cell Differentiation; Cell Line, Tumor; Cell Proliferation; Down-Regulation; gamma Catenin; Hematopoietic Stem Cells; Humans; Leukemia, Myeloid, Acute; Mice; Oncogene Proteins, Fusion; Phenotype; Signal Transduction; Sulindac; Time Factors; Wnt Proteins

Treatment of patients suffering from myelodysplastic syndromes and secondary acute myeloid leukemia after MDS is often unsuccessful. Pro-apoptosis with arsenic trioxide has recently been proposed as a novel therapeutic approach. Exisulind is another potentially pro-apoptotic agent, and therefore, we investigated its influence on proliferation, differentiation, cell cycle and apoptosis in two sAML/MDS cell lines, one de-novo AML cell line and healthy CD34+ bone marrow cells. Treatment of sAML/MDS cells with Exisulind clearly inhibited colony formation in the CFU-assays. Interestingly, Exisulind did not alter the percentages of sAML/MDS cells in G1-, G2-, M- or S-phase, but reduced proliferation and induced apoptosis in this cell type. Exisulind had no effect on de-novo AML or normal CD34+ cells. We detected increased c-Jun NH2-terminal kinase activity in sAML/MDS cells treated with Exisulind. Adding a specific JNK-inhibitor to Exisulind-treated sAML/MDS cells partly abrogated apoptosis, thus proving that Exisulind-mediated apoptosis in sAML/MDS cells is dependent on JNK activation. We conclude that JNK is one mediator of apoptosis in sAML/MDS cells treated with Exisulind. Moreover, our data strongly suggests to explore the potential use of Exisulind as a novel, pro-apoptotic therapy for patients with MDS and sAML/MDS.

Topics: Anti-Inflammatory Agents, Non-Steroidal; Antigens, CD34; Apoptosis; Bone Marrow Cells; Cell Line, Tumor; Cell Proliferation; Cells, Cultured; Colony-Forming Units Assay; GADD45 Proteins; Gene Expression Regulation, Neoplastic; Humans; Intracellular Signaling Peptides and Proteins; JNK Mitogen-Activated Protein Kinases; Leukemia, Myeloid, Acute; Myelodysplastic Syndromes; Sulindac; Time Factors

Topics: Acute Disease; Anemia, Aplastic; Female; Humans; Indenes; Leukemia, Myeloid, Acute; Middle Aged; Sulindac