Targeting histone methylation to reprogram the transcriptional state that drives survival of drug-tolerant myeloid leukemia persisters.

Although chemotherapy induces complete remission in the majority of acute myeloid leukemia (AML) patients, many face a relapse. This relapse is caused by survival of chemotherapy-resistant leukemia (stem) cells (measurable residual disease; MRD). Here, we demonstrate that the anthracycline doxorubicin epigenetically reprograms leukemia cells by inducing histone 3 lysine 27 (H3K27) and H3K4 tri-methylation.

The Novel Oral BET-CBP/p300 Dual Inhibitor NEO2734 Is Highly Effective in Eradicating Acute Myeloid Leukemia Blasts and Stem/Progenitor Cells.

Acute myeloid leukemia (AML) is a disease characterized by transcriptional dysregulation that results in a block in differentiation and aberrant self-renewal. Inhibitors directed to epigenetic modifiers, aiming at transcriptional reprogramming of AML cells, are currently in clinical trials for AML patients. Several of these inhibitors target bromodomain and extraterminal domain (BET) proteins, cyclic AMP response binding protein-binding protein (CBP), and the E1A-interacting protein of 300 kDa (p300), affecting histone acetylation.

Escape From Treatment; the Different Faces of Leukemic Stem Cells and Therapy Resistance in Acute Myeloid Leukemia.

Standard induction chemotherapy, consisting of an anthracycline and cytarabine, has been the first-line therapy for many years to treat acute myeloid leukemia (AML). Although this treatment induces complete remissions in the majority of patients, many face a relapse (adaptive resistance) or have refractory disease (primary resistance). Moreover, older patients are often unfit for cytotoxic-based treatment.

IGFBP7 activates retinoid acid-induced responses in acute myeloid leukemia stem and progenitor cells.

Treatment of acute promyelocytic leukemia (APL) with all-trans retinoic acid (ATRA) in combination with low doses of arsenic trioxide or chemotherapy leads to exceptionally high cure rates (>90%). ATRA forces APL cells into differentiation and cell death. Unfortunately, ATRA-based therapy has not been effective among any other acute myeloid leukemia (AML) subtype, and long-term survival rates remain unacceptably low; only 30% of AML patients survive 5 years after diagnosis.

IGFBP7 Induces Differentiation and Loss of Survival of Human Acute Myeloid Leukemia Stem Cells without Affecting Normal Hematopoiesis.

Leukemic stem cells (LSCs) are thought to be the major cause of the recurrence of acute myeloid leukemia (AML) due to their potential for self-renewal. To identify therapeutic strategies targeting LSCs, while sparing healthy hematopoietic stem cells (HSCs), we performed gene expression profiling of LSCs, HSCs, and leukemic progenitors all residing within the same AML bone marrow and identified insulin-like growth factor-binding protein 7 (IGFBP7) as differentially expressed. Low IGFBP7 is a feature of LSCs and is associated with reduced chemotherapy sensitivity.

Primary acute myeloid leukemia cells with overexpression of EVI-1 are sensitive to all-trans retinoic acid.

Enhanced expression of ecotropic viral integration site 1 (EVI-1) occurs in ∼10% of acute myeloid leukemia (AML) patients and is associated with a very poor disease outcome. Patients with EVI-1-positive AML have poor initial responses to chemotherapy and high relapse rates, indicating an urgent need for alternative treatment strategies improving clinical outcome for these patients. Because treatment of acute promyelocytic patients with all-trans retinoic acid (ATRA) has improved the survival of these patients substantially, we investigated whether ATRA might also be effective for the subgroup of AML patients with EVI-1 overexpression.

Attenuation of microRNA-126 expression that drives CD34+38- stem/progenitor cells in acute myeloid leukemia leads to tumor eradication.

Despite high remission rates after therapy, 60% to 70% of patients with acute myeloid leukemia (AML) do not survive 5 years after their initial diagnosis. The main cause of treatment failures may be insufficient eradication of a subpopulation of leukemic stem-like cells (LSC), which are thought to be responsible for relapse by giving rise to more differentiated leukemic progenitors (LP). To address the need for therapeutic targets in LSCs, we compared microRNA (miRNA) expression patterns in highly enriched healthy CD34(+)CD38(-) hematopoietic stem cells (HSC), CD34(+)CD38(-) LSCs, and CD34(+)CD38(+) LPs, all derived from the same patients' bone marrow (BM) specimens.

MicroRNA profiling can classify acute leukemias of ambiguous lineage as either acute myeloid leukemia or acute lymphoid leukemia.

Purpose: Classification of acute leukemia is based on the commitment of leukemic cells to the myeloid or the lymphoid lineage. However, a small percentage of acute leukemia cases lack straightforward immunophenotypical lineage commitment. These leukemias of ambiguous lineage represent a heterogeneous category of acute leukemia that cannot be classified as either acute myeloid leukemia (AML) or acute lymphoid leukemia (ALL).

Correlation of minimal residual disease cell frequency with molecular genotype in patients with acute myeloid leukemia.

Background: About 70-80 percent of patients with acute myeloid leukemia enter complete remission, but at least half of these patients who achieve remission go on to relapse. Improved treatment is likely to come from increasing the time to relapse, especially for younger patients. With the vastly increasing number of targeted therapies there is a strong need for short-term end-points to efficiently test such therapies for further pursuance.

Concurrent methylation of promoters from tumor associated genes predicts outcome in acute myeloid leukemia.

By assessment of the methylation status of 25 candidate tumor suppressor genes (TSGs) in 119 acute myeloid leukemia (AML) patients and 5 controls, we aimed to determine whether simultaneous methylation of multiple TSGs exerts prognostic impact. Methylation-specific multiplex ligation probe amplification (MS-MLPA) revealed methylation of at least one TSG in 59/119 patients, while no methylation was found in controls. Methylation of different TSGs within patients was substantially correlated (intra-class correlation; 0.

The novel bispecific diabody alphaCD40/alphaCD28 strengthens leukaemic dendritic cell-induced T-cell reactivity.

Dendritic cell (DC)-based immunotherapy faces new challenges because the efficacy of DC vaccines in clinical trials has been inconsistent. Strategies to improve immune responses induced by DC are currently being explored. We have recently shown the feasibility of generating fully functional DC from acute myeloid leukaemic (AML) blasts, but with varying expression levels of the important costimulatory molecule CD86.

Inhibition of the intrinsic apoptosis pathway downstream of caspase-9 activation causes chemotherapy resistance in diffuse large B-cell lymphoma.

Purpose: Inhibition of the apoptosis cascade is an important cause of therapy resistance in diffuse large B-cell lymphomas (DLBCL). In this study, we investigated possible mechanisms and expression levels of apoptosis-related genes in the apoptosis pathway that may be responsible for differences in chemotherapy sensitivity between DLBCL patients.

Experimental Design: Twenty-eight DLBCL patient samples were investigated for their expression levels of apoptosis-related genes using reverse transcription-multiplex ligation-dependent probe amplification analysis.

Activated intrinsic apoptosis pathway is a key related prognostic parameter in acute myeloid leukemia.

Purpose: By parallel assessment of multiple apoptosis-related transcripts, we aimed to refine the current concept of apoptosis resistance in acute myeloid leukemia (AML) and identify the combination of genes best predicting overall survival (OS).

Patients And Methods: The reverse transcriptase multiplex ligation-dependent probe amplification technique was used for simultaneous quantification of 31 apoptosis-related transcripts in viable (7AAD-/AnnexinV-) blasts (CD45dim) from bone marrow aspirates of 120 newly diagnosed AML patients. By forward selection, a prognosis-predicting gene expression profile was constructed.

Assessment and clinical significance of micrometastases in lymph nodes of head and neck cancer patients detected by E48 (Ly-6D) quantitative reverse transcription-polymerase chain reaction.

The presence of lymph node metastases is the major determinant for prognosis in head and neck squamous cell carcinoma (HNSCC). It is at present unknown whether the same holds true for the presence of histologically undetectable micrometastases. We analyzed 456 histologically tumor-negative lymph nodes of 23 HNSCC patients without (pN0) and 18 patients with one or two tumor-positive lymph nodes (pN+) in their neck dissection specimens at histopathologic examination.

Quantitative molecular detection of minimal residual head and neck cancer in lymph node aspirates.

Purpose: Staging of the clinically N(0) neck in patients with head and neck squamous cell carcinoma (HNSCC) using ultrasound-guided, fine needle aspiration cytology (USgFNAC) has a false-negative rate of approximately 20% that might be caused by inaccurate cytology. Molecular analysis of aspirate residues might reduce the false-negative rate, and we therefore set up a quantitative reverse transcription-PCR (Q-RT-PCR) assay based on TaqMan technology using the squamous cell-specific antigen E48 (Ly-6D) as molecular marker.

Experimental Design: The detection limit of the assay was determined in reconstruction experiments.

Mutated p53 as a molecular marker for the diagnosis of head and neck cancer.

In total, 10-30% of patients with head and neck squamous cell carcinoma (HNSCC) develop local recurrences despite seemingly adequate tumour resection. This may result from minimal residual cancer (MRC): small numbers of tumour cells left behind in the surgical margins, undetectable by routine histopathology. In recent studies, p53 mutations have been considered as selective and sensitive DNA markers of cancer cells.