Polysomy 8 defines a clinico-cytogenetic entity representing a subset of myeloid hematologic malignancies associated with a poor prognosis: report on a cohort of 12 patients and review of 105 published cases.

Tetrasomy, pentasomy, and hexasomy 8 (polysomy 8) are relatively rare compared to trisomy 8. Here we report on a series of 12 patients with acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), or myeloproliferative disorder (MPD) associated with polysomy 8 as detected by conventional cytogenetics and fluorescence in situ hybridization (FISH). In an attempt to better characterize the clinical and hematological profile of this cytogenetic entity, our data were combined with those of 105 published patients. Tetrasomy 8 was the most common presentation of polysomy 8. In 60.7% of patients, polysomy 8 occurred as part of complex changes (16.2% with 11q23 rearrangements). No cryptic MLL rearrangements were found in cases in which polysomy 8 was the only karyotypic change. Our study demonstrates the existence of a polysomy 8 syndrome, which represents a subtype of AML, MDS, and MPD characterized by a high incidence of secondary diseases, myelomonocytic or monocytic involvement in AML and poor overall survival (6 months). Age significantly reduced median survival, but associated cytogenetic abnormalities did not modify it. Cytogenetic results further demonstrate an in vitro preferential growth of the cells with a high level of aneuploidy suggesting a selective advantage for polysomy 8 cells.

TAF15 and the leukemia-associated fusion protein TAF15-CIZ/NMP4 are cleaved by caspases-3 and-7

Caspases are central players in proteolytic pathways that regulate cellular processes Such as apoptosis and differentiation. To accelerate the discovery of novel caspase substrates we developed a method combining in silico screening and in vitro validation. With this approach, we identified TAH15 as a novel caspase Substrate in a trial Study. We find that TAF15 was specifically cleaved by caspases-3 and -7. Site-directed mutagenesis revealed the consensus sequence (106)DQPD/Y(110) as the only site recognized by these caspases. Surprisingly, TAF15 was cleaved at more than one site in staurosporine-treated Jurkat cells. In addition, we generated two oncogenic TAF15-CIZ/NMP4-fused proteins which have been found in acute myeloid leukemia and demonstrate that caspases-3 and -7 cleave the fusion proteins at one single site. Broad application of this combination approach should expedite identification of novel caspase-interacting proteins and provide new insights into the regulation of caspase pathways leading to cell death in normal and cancer cells. (C) 2009 Elsevier Inc. All rights reserved.

Antibody-targeted horseradish peroxidase associated with indole-3-acetic acid induces apoptosis in vitro in hematological malignancies

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

p-iodophenol-enhanced luminol chemiluminescent assay applied to discrimination between acute lymphoblastic and minimally differentiated acute myeloid (FAB-M0) or acute megakaryoblastic (FAB-M7) leukemias

Introduction: In this report, we propose the application of the p-iodophenol-enhanced luminol chemiluminescent technique to the determination of peroxidase (myeloperoxidase and/or platelet peroxidase) activity in blasts of minimally differentiated acute myeloblastic leukemia (AML-M0) and acute megakaryoblastic leukemia (AML-M7).Methods: the frozen blast cells from 29 patients were thawed and submitted to the optimized protocol.Results: All cases of AML-M7 and AML-M0 exhibited integrated light emission greater than 73 (10(2) mV x s), which was the arbitrary cutoff point set for the discrimination between AML and acute lymphoblastic leukemia (ALL) (mean + 3 x s.d. of ALL samples, n = 10). In addition, five out of seven cases of AML-M0 showed results above the Cutoff point.Conclusion: This highly sensitive enhanced chemiluminescent technique may be applied to discriminate between ALL and AML-M7 or AML-M1 cases, and most AML-M0 cases. It is very simple, cheap and easy to perform compared to other procedures used to measure MPO activity in AML-leukemias including AML-M7 and AML-M0.

Simultaneous Occurrence of Biphenotypic T Cell/Myeloid Lesions Involving t(12;13)(p13;q14) in a Pediatric Patient

This paper chronicles a 2-year-old girl who presented with acute leukemia/lymphoma syndrome of the T cell immuno-phenotype. At this time, the cytogenetic analysis of her bone marrow cells showed a reciprocal translocation between the short arm of chromosome 12 and the long arm of chromosome 13, t(12;13)(p13;q14). The immunophenotyping of bone marrow blast cells by flow cytometry revealed a population of cells positive for CD56, CD117, CD45, partial CD33, partial HLA-DR, CD13, CD7, CD2 and CD5. Therefore, a diagnosis of acute leukemia with a mixed T cell/myeloid phenotype was made. The patient had a poor response to classic T cell acute lymphocytic leukemia/lymphoma therapy; thus, her treatment was changed to a myeloid leukemia protocol, which produced a good response. She underwent a successful cord blood transplantation from an unrelated HLA partially matched donor. The coexistence of these two phenotypes prompts questions about the existence of clonal instability, which might influence the choice of therapy. The rarity of the t(12;13)(p13;q14) and the coexistence of T cell/myeloid markers suggest a nonrandom association. To the best of our knowledge, this is the first reported case in which a cell clone bearing a t(12;13)(p13;q14) translocation in a mixed T cell/myeloid lesion was detected. Copyright (C) 2012 S. Karger AG, Basel

CYP3A5 and NAT2 gene polymorphisms: role in childhood acute lymphoblastic leukemia risk and treatment outcome

Susceptibility to acute lymphoblastic leukemia can be highly influenced by genetic polymorphisms in metabolizing enzyme genes of environmental carcinogens. This study aimed to evaluate the impact of the CYP3A5 and NAT2 metabolizing enzyme polymorphisms on the risk of childhood acute lymphoblastic leukemia. The analysis was conducted on 204 ALL patients and in 364 controls from a Brazilian population, using PCR-RFLP. The CYP3A5*3 polymorphic homozygous genotype was more frequent among ALL patients and the *3 allele variant was significantly associated with increased risk of childhood ALL (OR = 0.29; 95% CI, 0.14-0.60). The homozygous polymorphic genotype for the *6 allele variant was extremely rare and found in only two individuals. The heterozygous frequencies were similar for the ALL group and the control group. No significant differences were observed between the groups analyzed regarding NAT2 variant polymorphisms. None of the polymorphisms analyzed was related to treatment outcome. The results suggest that CYP3A5*3 polymorphism may play an important role in the risk of childhood ALL.

The impact of medical education and networking on the outcome of leukemia treatment in developing countries. The experience of International Consortium on Acute Promyelocytic Leukemia (IC-APL)

Objectives: Several clinical trials conducted in Europe and US reported favorable outcomes of patients with APL treated with the combination of all trans retinoic acid (ATRA) and anthracyclines. Nevertheless, the results observed in developing countries with the same regimen was poorer, mainly due to high early mortality mainly due bleeding. The International Consortium on Acute Promyelocytic Leukemia (IC-APL) is an initiative of the International Members Committee of the ASH and the project aims to reduce this gap through the establishment of international network, which was launched in Brazil, Mexico and Uruguay. Methods: The IC-APL treatment protocol is similar to the PETHEMA 2005, but changing idarubicin to daunorubicin. All patients with a suspected diagnosis of APL were immediately started on ATRA, while bone marrow samples were shipped to a national central lab where genetic verification of the diagnosis was performed. The immunofluorescence using an anti-PML antibody allowed a rapid confirmation of the diagnosis and, the importance of supportive measures was reinforced. Results: The interim analysis of 97 patients enrolled in the IC-APL protocol showed that complete remission (CR) rate was 83% and the 2-year overall survival and disease-free survival were 80% and 90%, respectively. Of note, the early mortality rate was reduced to 7.5%. Discussion: The results of IC-APL demonstrate the impact of educational programs and networking on the improvement of the leukemia treatment outcome in developing countries.

Impact of pretransplant minimal residual disease after cord blood transplantation for childhood acute lymphoblastic leukemia in remission: an Eurocord, PDWP-EBMT analysis

To address the prognostic value of minimal residual disease (MRD) before unrelated cord blood transplantation (UCBT) in children with acute lymphoblastic leukemia (ALL), we analyzed 170 ALL children transplanted in complete remission (CR) after myeloablative conditioning regimen. In all, 72 (43%) were in first CR (CR1), 77 (45%) in second CR (CR2) and 21 (12%) in third CR (CR3). The median interval from MRD quantification to UCBT was 18 days. All patients received single-unit UCBT. Median follow-up was 4 years. Cumulative incidence (CI) of day-60 neutrophil engraftment was 85%. CI of 4 years relapse was 30%, incidence being lower in patients with negative MRD before UCBT (hazard ratio (HR) = 0.4, P = 0.01) and for those transplanted in CR1 and CR2 (HR = 0.3, P = 0.002). Probability of 4 years leukemia-free survival (LFS) was 44%, (56, 44 and 14% for patients transplanted in CR1, CR2 and CR3, respectively (P = 0.0001)). Patients with negative MRD before UCBT had better LFS after UCBT compared with those with positive MRD (54% vs 29%; HR = 2, P = 0.003). MRD assessment before UCBT for children with ALL in remission allows identifying patients at higher risk of relapse after transplantation. Approaches that may decrease relapse incidence in children given UCBT with positive MRD should be investigated to improve final outcomes. Leukemia (2012) 26, 2455-2461; doi:10.1038/leu.2012.123

In vitro characterization of human AML-reactive CTL clones generated from the naive subset of healthy donors and adoptive transfer into leukemia-engrafted NSG mice

Acute myeloid leukemia (AML) is a very aggressive cancer of the hematopoietic system. Chemotherapy and immunotherapeutical approaches including hematopoietic stem cell transplantation (HSCT) and donor lymphocyte infusion (DLI) are the only curative options available. The beneficial graft-versus-leukemia (GVL) effect of cellular immunotherapy is mostly mediated by donor-derived CD8+ T lymphocytes that recognize minor histocompatibility antigens (mHags) and leukemia-associated antigens (LAAs) presented on the surface of AML blasts (Falkenburg et al. 2008; Kolb 2008). A main complication is graft-versus-host disease (GVHD) that can be induced when cytotoxic T lymphocytes (CTLs) recognize broadly expressed antigens. To reduce the risk of GVHD, specific allogeneic T-cell therapy inducing selective GVL responses could be an option (Barrett & Le Blanc 2010; Parmar et al. 2011; Smits et al. 2011). This requires efficient in vitro strategies to generate AML-reactive T cells with an early differentiation phenotype as well as vigorous effector functions and humanized mouse models to analyze the anti-leukemic potential of adoptively transferred T cells in vivo. In this study, AML-reactive CTL clones and oligoclonal T-cell lines could be reliably generated from the naive subset of healthy HLA-class I-identical donors by stimulation with primary AML blasts in mini-mixed-lymphocyte / leukemia cultures (MLLCs) in eight different patient / donor pairs. These CTLs were promising candidates for cellular immunotherapy because of their relatively early differentiation phenotype and strong proliferative and lytic capabilities. The addition of the common γ-chain cytokine IL-21 to the stimulation protocol enabled more precursors to develop into potent leukemia-reactive CTLs, presumably by its beneficial effects on cell survival and antigen-specific proliferation during the first weeks of cultures. It also strengthened the early-stage phenotype. Three long-term cultured CTLs exemplarily transferred into leukemia-engrafted immunodeficient NSG mice mediated a significant reduction of the leukemic burden after a single transfusion. These results demonstrate that CTL clones with reactivity to patient-derived AML blasts can be isolated from the naive compartment of healthy donors and show potent anti-leukemic effects in vivo. The herein described allo-MLLC approach with in vitro “programmed” naive CTL precursors independent of a HSCT setting is a valuable alternative to the conventional method of isolating in vivo primed donor CTLs out of patients after transplantation (Kloosterboer et al. 2004; Warren et al. 2010). This would make leukemia-reactive CTLs already available at the time point of HSCT, when residual leukemia disease is minimal and the chances for complete leukemia eradication are high. Furthermore, leukemia-reactive CTLs effectively expanded by this in vitro protocol can be used as screening populations to identify novel candidate LAAs and mHags for antigen-specific immunotherapy.

Zelluläre und molekulare Mechanismen der angeborenen Immunität

Die myeloide Zelllinie MUTZ-3 konnte als geeignetes Modellsystem zur Charakterisierung der TREM-1-Signaltransduktion etabliert werden, da diese TREM-1 und dessen essentielles Adaptermoleküle DAP12 funktional exprimiert. Übereinstimmend mit bisherigen Daten wurden die Kinasen PI3K und p38-MAPK als wichtige Regulatoren in der Signalweiterleitung nach TREM-1-Aktivierung identifiziert, wobei sich einige Unterschiede in der exakten Signalhierarchie zwischen monozytären und granulozytären Zellen ergaben. So erfolgt die Aktivierung von PI3K und p38-MAPK in PMN unabhängig voneinander und in monozytären Zellen findet die Aktivierung von p38-MAPK vor der Akt-Phosphorylierung statt und ist für Letztere notwendig. Zudem ist die Ca2+-Mobilisierung in PMN nur von PI3K abhängig und in monozytären Zellen von PI3K und p38-MAPK. Bei der durch TLR- oder NLR-Koligation gesteigerten TREM-1-Aktivierung sind PI3K und p38-MAPK ebenfalls zentrale Regulatoren. Es ergaben sich ebenfalls Unterschiede in der exakten TREM-1-Signaltransduktion.rnrnEin Mausmodell für invasive Aspergillose (IA) wurde erfolgreich etabliert, wobei die wichtige Rolle der PMN bei der Abwehr von Pilzinfektionen durch deren Depletion mit unterschiedlichen Antikörpern belegt wurde. Für das Abtöten von A. fumigatus-Konidien sind oxidative und nicht-oxidative PMN-Effektormechanismen notwendig. Dabei konnte die essentielle Rolle der oxidativen PMN-Effektorfunktionen anhand NADPH-Oxidase-defizienter p47phox-/- und gp91phox-/- Mäuse für das Überleben von Pilzinfektionen gezeigt werden. Dagegen war die Infektion von Neutrophiler Elastase defizienter ELANE Mäuse nicht letal. Dies deutet darauf hin, dass diese als prototypische Serinprotease und wichtiger Bestandteil der NET-Formation nicht essentiell für das Überleben von IA ist oder durch andere, nicht-oxidative Effektormechanismen kompensiert werden kann. Keinen Einfluss auf die IA hatte die Depletion von Arginin mittels ADI-PEG, da weder das Überleben der Mäuse noch das Abtöten der Pilzkonidien beeinflusst wurde. Außerdem wurden keine Veränderung in der Einwanderung und Aktivierung von PMN nach Infektion quantifiziert. Dagegen induzierte die Defizienz in ADAMTS13 (ADAMTS13-/- Mäuse) eine verminderte Rekrutierung von PMN, einhergehend mit erhöhter Mortalität, vermindertem Abtöten von A. fumigatus-Konidien und erhöhter Schädigung der Lunge bei IA. Da in vitro keine generellen oder pilzspezifischen Defekte der PMN quantifiziert wurden, muss ADAMTS13 die Einwanderung der PMN beeinflussen. Normalerweise spaltet die Protease ADAMTS13 den von-Willebrand-Faktor (vWF), der die Quervernetzung und das Anhaften von Blutplättchen an beschädigte Gefäßwände steuert. Ob und wie ADAMTS13 oder der vWF die verminderte PMN-Einwanderung bei Pilzinfektionen verursacht, muss weiter untersucht werden.rnrnZusammenfassend verbessern die erhaltenen Daten für eine zellspezifische TREM-1-Signaltransduktion, ein von oxidativen und nicht-oxidativen PMN-Effektorfunktionen abhängiges sowie Arginin-unabhängiges Abtöten vom Pilz A. fumigatus als auch der Einfluss von ADAMTS13 und vWF bei der Rekrutierung von PMN nach A. fumigatus-Infektion unser Verständnis der angeborenen Immunität. Diese Erkenntnisse dienen der zukünftigen Entwicklung von Therapien zur Behandlung von schweren Entzündungsreaktionen wie Aspergillose und Sepsis.

CLEC5A (MDL-1) is a novel PU.1 transcriptional target during myeloid differentiation

C-type lectin domain family 5, member A (CLEC5A), also known as myeloid DNAX activation protein 12 (DAP12)-associating lectin-1 (MDL-1), is a cell surface receptor strongly associated with the activation and differentiation of myeloid cells. CLEC5A associates with its adaptor protein DAP12 to activate a signaling cascade resulting in activation of downstream kinases in inflammatory responses. Currently, little is known about the transcriptional regulation of CLEC5A. We identified CLEC5A as one of the most highly induced genes in a microarray gene profiling experiment of PU.1 restored myeloid PU.1-null cells. We further report that CLEC5A expression is significantly reduced in several myeloid differentiation models upon PU.1 inhibition during monocyte/macrophage or granulocyte differentiation. In addition, CLEC5A mRNA expression was significantly lower in primary acute myeloid leukemia (AML) patient samples than in macrophages and granulocytes from healthy donors. Moreover, we found activation of a CLEC5A promoter reporter by PU.1 as well as in vivo binding of PU.1 to the CLEC5A promoter. Our findings indicate that CLEC5A expression in monocyte/macrophage and granulocytes is regulated by PU.1.

The multicenter trial SAKK 37/95 of cladribine, cyclophosphamide and prednisone in the treatment of chronic lymphocytic leukemias and low-grade non-Hodgkin's lymphomas

A multicenter trial was performed to confirm the therapeutic efficacy and the toxicity profile of the combination of cladribine, cyclophosphamide and prednisone in low-grade non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL). Twenty-three adults with previously treated (61%) or untreated (39%) NHL International Working Formulation A or Binet B and C CLL were administered cladribine 0.1 mg/kg/day as a subcutaneous bolus for 5 days, intravenous cyclophosphamide 500 mg/m2 on day 1, and oral prednisone 40 mg/m2 on days 1-5, every 4 weeks. Unexpected early hematological toxicities led to dose modifications for pretreated patients who received cladribine for 3 days only up to a maximum of five courses. Responses were observed in 75%, with 7 patients obtaining a complete clinical and hematological response. Median duration of complete response was 9 months. Median time to progression or relapse was 31 months. Myelosuppression and infections were dose limiting whereas posttreatment complications, including fatalities, resulted from infections. Median overall survival time from trial entry was 60 months. Activity of the combination of cladribine, cyclophosphamide and prednisone was confirmed. However, in the specific setting of a multicenter trial, unexpected fatal infectious episodes occurred in pretreated patients. Great caution is thus required in these susceptible patients and the routine use of corticosteroids should probably be abandoned.

Transcriptional dysregulation during myeloid transformation in AML

The current paradigm on leukemogenesis indicates that leukemias are propagated by leukemic stem cells. The genomic events and pathways involved in the transformation of hematopoietic precursors into leukemic stem cells are increasingly understood. This concept is based on genomic mutations or functional dysregulation of transcription factors in malignant cells of patients with acute myeloid leukemia (AML). Loss of the CCAAT/enhancer binding protein-alpha (CEBPA) function in myeloid cells in vitro and in vivo leads to a differentiation block, similar to that observed in blasts from AML patients. CEBPA alterations in specific subgroups of AML comprise genomic mutations leading to dominant-negative mutant proteins, transcriptional suppression by leukemic fusion proteins, translational inhibition by activated RNA-binding proteins, and functional inhibition by phosphorylation or increased proteasomal-dependent degradation. The PU.1 gene can be mutated or its expression or function can be blocked by leukemogenic fusion proteins in AML. Point mutations in the RUNX1/AML1 gene are also observed in specific subtypes of AML, in addition to RUNX1 being the most frequent target for chromosomal translocation in AML. These data are persuasive evidence that impaired function of particular transcription factors contributes directly to the development of human AML, and restoring their function represents a promising target for novel therapeutic strategies in AML.

Tumor suppressor genes in myeloid differentiation and leukemogenesis

Tumor suppressor genes, such as p53, RB, the INK4-ARF family and PML, suppress malignant transformation by regulating cell cycle progression, ensuring the fidelity of DNA replication and chromosomal segregation, or by inducing apoptosis in response to potentially deleterious events. In myeloid leukemia, hematopoietic differentiation resulting from highly coordinated, stage-wise expression of myeloid transcription and soluble signaling factors is disrupted leading to a block in terminal differentiation and uncontrolled proliferation. This virtually always involves functional inactivation or genetic disruption of one or several tumor suppressor genes in order to circumvent their checkpoint control and apoptosis-inducing functions. Hence, reactivation of tumor suppressor gene function has therapeutic potential and can possibly enhance conventional cytotoxic chemotherapy. In this review, we focus on the role of different tumor suppressor genes in myeloid differentiation and leukemogenesis, and discuss implications for therapy.

Dasatinib inhibits the growth of molecularly heterogeneous myeloid leukemias.

PURPOSE: Dasatinib is a dual Src/Abl inhibitor recently approved for Bcr-Abl+ leukemias with resistance or intolerance to prior therapy. Because Src kinases contribute to multiple blood cell functions by triggering a variety of signaling pathways, we hypothesized that their molecular targeting might lead to growth inhibition in acute myeloid leukemia (AML). EXPERIMENTAL DESIGN: We studied growth factor-dependent and growth factor-independent leukemic cell lines, including three cell lines expressing mutants of receptor tyrosine kinases (Flt3 or c-Kit) as well as primary AML blasts for responsiveness to dasatinib. RESULTS: Dasatinib resulted in the inhibition of Src family kinases in all cell lines and blast cells at approximately 1 x 10(-9) mol/L. It also inhibited mutant Flt3 or Kit tyrosine phosphorylation at approximately 1 x 10(-6) mol/L. Mo7e cells expressing the activating mutation (codon 816) of c-Kit were most sensitive to growth inhibition with a GI(50) of 5 x 10(-9) mol/L. Primary AML blast cells exhibited a growth inhibition of <1 x>10(-6) mol/L. Cell lines that showed growth inhibition at approximately 1 x 10(-6) mol/L showed a G(1) cell cycle arrest and correlated with accumulation of p21 and p27 protein. The addition of rapamycin or cytotoxic agents enhanced growth inhibition. Dasatinib also caused the apoptosis of Mo7e cells expressing oncogenic Kit. CONCLUSIONS: Although all of the precise targets for dasatinib are not known, this multikinase inhibitor causes either growth arrest or apoptosis in molecularly heterogeneous AML. The addition of cytotoxic or targeted agents can enhance its effects.