Targeted therapy in acute myeloid leukemia:current status and new insights from a proteomic perspective

Introduction: The biological heterogeneity of acute myeloid leukemia (AML) complicates personalized medicine. Individual prognosis is typically based on the presence of chromosomal and genetic lesions. Nevertheless, these classifications often lack a priori information about response to therapy. Since the protein expression landscape reflects the functional activity state of cells, we hypothesize that analyzing this can be used for the identification of protein activity markers to provide better risk stratification as well as may provide targeted therapeutic guidance in AML. Areas covered: Herein, we review recently new adopted drugs in the treatment for AML and discuss how quantitative proteomic techniques may contribute to better therapeutic selection in AML. Expert commentary: The net functional state of the cell is defined by the activity of protein within all the pathways that are active in the cell. Recognition of the proteomic profile of the leukemic blast could, therefore, complement current classification systems by providing a better a priori description of what pathways are important within a cell as a guide to the selection of therapy for the patient

Can kinomics and proteomics bridge the gap between pediatric cancers and newly designed kinase inhibitors?

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Epidermal growth factor receptor is expressed and active in a subset of acute myeloid leukemia

The epidermal growth factor receptor (EGFR) inhibitor erlotinib has been shown to induce complete remission of acute myeloid leukemia (AML) in two patients with concurrent lung cancer and raised attention for a role of EGFR in AML whereas a recent phase II clinical study with gefitinib in AML demonstrated a negative result on the outcome. However, from several studies, EGFR expression in AML is poorly defined and the role of EGFR in AML remains unclear. Herein, we report the results of EGFR expression in AML of large cohorts of adult and pediatric AML patients with the data of total protein and phosphorylation levels of EGFR. Our data conclude that there is the expression of EGFR at the protein level in a subset of AML, which was identified to be functionally active in similar to 15 % of AML patients. This suggests that future studies need to be conducted with a subset of AML patients characterized by high EGFR expression

Loss of H3K27 methylation identifies poor outcomes in adult-onset acute leukemia

BackgroundAcute leukemia is an epigenetically heterogeneous disease. The intensity of treatment is currently guided by cytogenetic and molecular genetic risk classifications; however these incompletely predict outcomes, requiring additional information for more accurate outcome predictions. We aimed to identify potential prognostic implications of epigenetic modification of histone proteins, with a focus on H3K4 and H3K27 methylation marks in relation to mutations in chromatin, splicing and transcriptional regulators in adult-onset acute lymphoblastic and myeloid leukemia.ResultsHistone 3 lysine 4 di- and trimethylation (H3K4me2, H3K4me3) and lysine 27 trimethylation (H3K27me3) mark expression was evaluated in 241 acute myeloid leukemia (AML), 114 B-cell acute lymphoblastic leukemia (B-ALL) and 14T-cell ALL (T-ALL) patient samples at time of diagnosis using reverse phase protein array. Expression levels of the marks were significantly lower in AML than in B and T-ALL in both bone marrow and peripheral blood, as well as compared to normal CD34+ cells. In AML, greater loss of H3K27me3 was associated with increased proliferative potential and shorter overall survival in the whole patient population, as well as in subsets with DNA methylation mutations. To study the prognostic impact of H3K27me3 in the context of cytogenetic aberrations and mutations, multivariate analysis was performed and identified lower H3K27me3 level as an independent unfavorable prognostic factor in all, as well as in TP53 mutated patients. AML with decreased H3K27me3 demonstrated an upregulated anti-apoptotic phenotype. In ALL, the relative quantity of histone methylation expression correlated with response to tyrosine kinase inhibitor in patients who carried the Philadelphia cytogenetic aberration and prior smoking behavior.ConclusionThis study shows that proteomic profiling of epigenetic modifications has clinical implications in acute leukemia and supports the idea that epigenetic patterns contribute to a more accurate picture of the leukemic state that complements cytogenetic and molecular genetic subgrouping. A combination of these variables may offer more accurate outcome prediction and we suggest that histone methylation mark measurement at time of diagnosis might be a suitable method to improve patient outcome prediction and subsequent treatment intensity stratification in selected subgroups

Neurofibromatosis type 1 associated low grade gliomas:A comparison with sporadic low grade gliomas

AbstractNeurofibromatosis type 1 (NF1) is an autosomal dominant disorder, associated with a variable clinical phenotype including café-au-lait spots, intertriginous freckling, Lisch nodules, neurofibromas, optic pathway gliomas and distinctive bony lesions. NF1 is caused by a mutation in the NF1 gene, which codes for neurofibromin, a large protein involved in the MAPK- and the mTOR-pathway through RAS-RAF signalling.NF1 is a known tumour predisposition syndrome, associated with different tumours of the nervous system including low grade gliomas (LGGs) in the paediatric population. The focus of this review is on grade I pilocytic astrocytomas (PAs), the most commonly observed histologic subtype of low grade gliomas in NF1. Clinically, these PAs have a better prognosis and show different localisation patterns than their sporadic counterparts, which are most commonly associated with a KIAA1549:BRAF fusion.In this review, possible mechanisms of tumourigenesis in LGGs with and without NF1 will be discussed, including the contribution of different signalling pathways and tumour microenvironment. Furthermore we will discuss how increased understanding of tumourigenesis may lead to new potential targets for treatment

Peptide microarray of pediatric acute myeloid leukemia is related to relapse and reveals involvement of DNA damage response and repair

The majority of acute myeloid leukemia (AML) patients suffer from relapse and the exact etiology of AML remains unclear. The aim of this study was to gain comprehensive insights into the activity of signaling pathways in AML. In this study, using a high-throughput PepChip™ Kinomics microarray system, pediatric AML samples were analyzed to gain insights of active signal transduction pathway. Unsupervised hierarchical cluster analysis separated the AML blast profiles into two clusters. These two clusters were independent of patient characteristics, whereas the cumulative incidence of relapse (CIR) was significantly higher in the patients belonging to cluster-2. In addition, cluster-2 samples showed to be significantly less sensitive to various chemotherapeutic drugs. The activated peptides in cluster-1 and cluster-2 reflected the activity of cell cycle regulation, cell proliferation, cell differentiation, apoptosis, PI3K/AKT, MAPK, metabolism regulation, transcription factors and GPCRs signaling pathways. The difference between two clusters might be explained by the higher cell cycle arrest response in cluster-1 patients and higher DNA repair mechanism in cluster-2 patients. In conclusion, our study identifies different signaling profiles in pediatric AML in relation with CIR involving DNA damage response and repair

Very early discharge versus early discharge versus non-early discharge in children with cancer and febrile neutropenia

Background Chemotherapy-induced neutropenia is a common adverse effect in children with cancer. Due to the high relative risk of infections and infectious complications, standard care for children with cancer and febrile neutropenia consists of routine hospitalization and parenteral administration of broad-spectrum antibiotics. However, there are less serious causes of febrile neutropenia; in a subgroup of these children, lengthy in-hospital treatment might be unnecessary. Various research groups have studied the adjustment of standard care to shorten in-hospital treatment for children with cancer and febrile neutropenia at low risk for bacterial infections. However, most of these studies were not done in a randomized matter. Objectives To evaluate whether early discharge (mean/median of less than five days) from in-hospital treatment was not inferior to non-early discharge (mean/median of five days or more) and whether very early discharge (mean/median of less than 24 hours) was not inferior to early discharge, non-early discharge, or a combination of these, in children with cancer and febrile neutropenia. Search methods We searched the Cochrane Central Register of Controlled Trials (2015, issue 11), MEDLINE/PubMed (from 1945 to December 2015), EMBASE/Ovid (from 1980 to December 2015), the reference lists of relevant articles and review articles, and various conference proceedings (dependent on availability from 2005 to 2010 to 2013 to 2015). We scanned the International Standard Randomised Controlled Trials Number (ISRCTN) Register, the National Institute of Health Register for ongoing trials, and the World Health Organization (WHO) International Clinical Trials Registry Platform (ICTRP) on 9 January 2016. Selection criteria We included all randomized controlled trials and controlled clinical trials in which children with cancer and febrile neutropenia were divided in groups with different times of discharge. Data collection and analysis We used standard methods of Cochrane and its Childhood Cancer Group. Two independent review authors performed study selection, data extraction, and risk of bias assessment. We entered data extracted from the included studies into Review Manager 5 and undertook analyses according to the guidelines of the Cochrane Handbook for Systematic Reviews of Interventions. Main results We included two randomized controlled trials assessing very early, early, non-early (or a combination of these) discharge in children with cancer and febrile neutropenia. We graded the evidence as low quality; we downgraded for risk of bias and imprecision. One study, Santolaya 2004, consisted of 149 randomized low-risk episodes and compared early discharge (mean/median of less than five days) to non-early discharge (mean/median of five days or more). This study found no clear evidence of difference in treatment failure (risk ratio (RR) 0.91, 95% confidence interval (CI) 0.24 to 3.50, P value = 0.89 for rehospitalization or adjustment of antimicrobial treatment, or both; Fischer's exact P value = 0.477 for death) or duration of treatment (mean difference -0.3 days, 95% CI -1.22 to 0.62, P value = 0.52 for any antimicrobial treatment; mean difference -0.5 days, 95% CI -1.36 to 0.36, P value = 0.25 for intravenous antimicrobial treatment; mean difference 0.2 days, 95% CI -0.51 to 0.91, P value = 0.58 for oral antimicrobial treatment). Costs were lower in the early discharge group (mean difference USD -265, 95% CI USD -403.14 to USD -126.86, P value = 0.0002). The second included study, Brack 2012, consisted of 62 randomized low-risk episodes and compared very early discharge (mean/median of less than 24 hours) to early discharge (mean/median of less than five days). This study also found no clear evidence of difference in treatment failure (RR 0.54, 95% CI 0.15 to 1.89, P value = 0.34 for rehospitalization or adjustment of antimicrobial treatment (or both); Fischer's exact P value = 0.557 for death). Regarding duration of treatment, median duration of intravenous antimicrobial treatment was shorter in the very early discharge group (Wilcoxon's P value = 0.001, stated in the study) and median duration of oral antimicrobial treatment was shorter in the early discharge group (Wilcoxon's P = 0.001, stated in the study) as compared to one another. However, there was no clear evidence of difference in median duration of any antimicrobial treatment (Wilcoxon's P value = 0.34, stated in the study). Costs were not assessed in this study. Neither of the included studies assessed quality of life. Meta-analysis was not possible as the included studies assessed different discharge moments and used different risk stratification models. Authors' conclusions Very limited data were available regarding the safety of early discharge compared to non-early discharge from in-hospital treatment in children with cancer and febrile neutropenia and a low risk for invasive infection. The absence of clear evidence of differences in both studies could be due to lack of power. Evidently, there are still profound gaps regarding very early and early discharge in children with cancer and febrile neutropenia. Future studies that assess this subject should have a large sample size and aim to establish uniform and objective criteria regarding the identification of a low-risk febrile neutropenic episode

Addition of PTK787/ZK 222584 can lower the dosage of amsacrine to achieve equal amounts of acute myeloid leukemia cell death

Acute myeloid leukemia (AML) is a disease with a poor prognosis. It has been demonstrated that AML cells express the vascular endothelial growth factors, VEGFA and VEGFC, as well as kinase insert domain-containing receptor (VEGFR2), the main receptor for downstream effects, resulting in an autocrine pathway for cell survival. This study investigates the role of the VEGFR inhibitor PTK787/ZK 222584 in leukemic cell death, and the possibility of an additional effect on cell death by a chemotherapeutic drug, amsacrine. In three AML cell lines and 33 pediatric AML patient samples, we performed total cell-kill assays to determine the percentages of cell death achieved by PTK787/ZK 222584 and/or amsacrine. Both drugs induced AML cell death. Using a response surface analysis, we could show that, in cell lines as well as in primary AML blasts, an equal magnitude of leukemic cell death could be obtained when lower doses of the more toxic amsacrine were combined with low dosages of the less toxic VEGFR inhibitor. This study shows that PTK787/ ZK 222584 might have more clinical potential in AML when combined with a chemotherapeutic drug such as amsacrine. In future, it will be interesting to study whether the complications and the long-term effects of chemotherapy can be reduced by lowering the dosages of amsacrine, and by replacing it with other drugs with lower toxicity profiles, such as PTK787/ZK 222584

Peptide microarray profiling identifies phospholipase C gamma 1 (PLC-γ1) as a potential target for t(8;21) AML

The t(8;21) (q22;q22) chromosomal translocation is one of the most frequent genetic alterations in acute myeloid leukemia (AML) which has a need for improved therapeutic strategies. We found PLC-γ1 as one of the highest phosphorylated peptides in t(8;21) AML samples compared to NBM or CN-AML in our previous peptide microarray. PLC-γ1 is known to play a role in cancer progression, however, the impact of PLC-γ1 in AML is currently unknown. Therefore, we aimed to study the functional role of PLC-γ1 by investigating the cellular growth, survival and its underlying mechanism in t(8;21) AML.  In this study, PLC-γ1 expression was significantly higher in t(8;21) AML compared to other karyotypes. The PLC-γ1 protein expression was suppressed in AML1-ETO knock down cells indicating that it might induce kasumi-1 cell death. ShRNA-mediated PLC-γ1 knockdown in kasumi-1 cells significantly blocked cell growth, induced apoptosis and cell cycle arrest which was explained by the increased activation of apoptotic related and cell cycle regulatory protein expressions. Gene expression array analysis showed the up-regulation of apoptotic and DNA damage response genes together with the downregulation of cell growth, proliferation and differentiation genes in the PLC-γ1 suppressed kasumi-1 cells, consistent with the observed phenotypic effects. Importantly, PLC-γ1 suppressed kasumi-1 cells showed higher chemosensitivity to the chemotherapeutic drug treatments and lower cell proliferation upon hypoxic stress.  Taken together, these in vitro finding strongly support an important role for PLC-γ1 in the survival of t(8;21) AML mimicking kasumi-1 cells and identify PLC-γ1 as a potential therapeutic target for t(8;21) AML treatment

RPPA-based proteomics recognizes distinct epigenetic signatures in chronic lymphocytic leukemia with clinical consequences

The chronic lymphocytic leukemia (CLL) armamentarium has evolved significantly, with novel therapies that inhibit Bruton Tyrosine Kinase, PI3K delta and/or the BCL2 protein improving outcomes. Still, the clinical course of CLL patients is highly variable and most previously recognized prognostic features lack the capacity to predict response to modern treatments indicating the need for new prognostic markers. In this study, we identified four epigenetically distinct proteomic signatures of a large cohort of CLL and related diseases derived samples (n = 871) using reverse phase protein array technology. These signatures are associated with clinical features including age, cytogenetic abnormalities [trisomy 12, del(13q) and del(17p)], immunoglobulin heavy-chain locus (IGHV) mutational load, ZAP-70 status, Binet and Rai staging as well as with the outcome measures of time to treatment and overall survival. Protein signature membership was identified as predictive marker for overall survival regardless of other clinical features. Among the analyzed epigenetic proteins, EZH2, HDAC6, and loss of H3K27me3 levels were the most independently associated with poor survival. These findings demonstrate that proteomic based epigenetic biomarkers can be used to better classify CLL patients and provide therapeutic guidance