[New Drugs in the Treatment of Acute Myeloid Leukemia in the Elderly]

BACKGROUND

At the time of diagnosis, most patients with acute myeloid leukemia are older than 65 years of age. Treatment of this group of patients is challenging because they become less tolerant to aggressive chemotherapy with increasing age. Less than one-third of elderly patients are considered eligible for intensive treatment; nevertheless, the survival analysis for this population remains poor. Due to numerous comorbidities and an overall deteriorating condition, most elderly patients with acute myeloid leukemia receive only palliative or best supportive care, which are associated with a high mortality rate. New therapeutic approaches are expected to improve the overall survival and quality of life of this group of patients. These promising treatments include cell kinase inhibitors, cytotoxic agents, monoclonal antibodies, and epigenetic therapy including hypomethylating agents and inhibitors of isocitrate dehydrogenase and histone deacetylase. In monotherapy, these new drugs show lower levels of toxicity than those commonly used in chemotherapy; however, they do not lead to a better long-lasting treatment response. To enhance therapeutic efficacy, combinations of the above-mentioned treatments are often used, and, during clinical trials, combinations with standard cytostatics are also common. The promising results of these studies show that even low-toxicity therapies can lead to a better overall treatment response and to longer overall survival.

AIM

This article provides a brief overview of new drugs that are evaluated for their mechanism of effect, efficacy and toxicity in therapy of patients suffering from acute myeloid leukemia.Key words: acute myeloid leukemia - elderly - FLT3 inhibitors - epigenetic therapy - monoclonal antibodies The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 4. 11. 2016Accepted: 13. 12. 2016.

Atomic resolution elemental mapping using energy-filtered imaging scanning transmission electron microscopy with chromatic aberration correction

This paper addresses a novel approach to atomic resolution elemental mapping, demonstrating a method that produces elemental maps with a similar resolution to the established method of electron energy-loss spectroscopy in scanning transmission electron microscopy. Dubbed energy-filtered imaging scanning transmission electron microscopy (EFISTEM) this mode of imaging is, by the quantum mechanical principle of reciprocity, equivalent to tilting the probe in energy-filtered transmission electron microscopy (EFTEM) through a cone and incoherently averaging the results. In this paper we present a proof-of-principle EFISTEM experimental study on strontium titanate. The present approach, made possible by chromatic aberration correction, has the advantage that it provides elemental maps which are immune to spatial incoherence in the electron source, coherent aberrations in the probe-forming lens and probe jitter. The veracity of the experiment is supported by quantum mechanical image simulations, which provide an insight into the image-forming process. Elemental maps obtained in EFTEM suffer from the effect known as preservation of elastic contrast, which, for example, can lead to a given atomic species appearing to be in atomic columns where it is not to be found. EFISTEM very substantially reduces the preservation of elastic contrast and yields images which show stability of contrast with changing thickness. The experimental application is demonstrated in a proof-of-principle study on strontium titanate.

[Molecular Genetic Testing for Acute Myeloid Leukemia]

BACKGROUND

Acute myeloid leukemia (AML) is a clinically complex and very heterogeneous disease at the molecular level. Conventional cytogenetic analysis and FISH (fluorescence in situ hybridization) tests provide important information about the biological and clinical background of the disease and enable the classification of AML patients into three risk groups. However, up to half of patients have normal cytogenetics. Determining prognosis and treatment strategies in this group of patients is challenging. The development of molecular genetic methods, including next generation sequencing in the last decade, has led to the discovery of a number of recurrent mutations that have contributed to increasing the accuracy of prognosis of those patients with cytogenetically normal AML. Besides the prognostic value of these mutations, they may also be used to monitor minimal residual disease during and after treatment of AML and additionally constitute potential targets for the development of new therapeutic agents. The importance of molecular genetic testing of all patients with AML is highlighted by the WHO classification of 2008 in which subgroups of AML are purely defined by molecular genetics markers.

AIM

In this article, we provide an overview of the most significant mutations in patients with cytogenetically normal AML. We describe their significance for prognosis, their importance in monitoring minimal residual disease, and their potential for the development of new targeted therapies. Further, we briefly draw attention to the significance of gene mutation accumulation in clonal disease development and how it affects the time of AML relapse.

Nanometre-scale 3D defects in Cr2AlC thin films

MAX-phase Cr₂AlC containing thin films were synthesized by magnetron sputtering in an industrial system. Nanometre-scale 3D defects are observed near the boundary between regions of Cr₂AlC and of the disordered solid solution (CrAl)_xC_y. Shrinkage of the Cr-Cr interplanar distance and elongation of the Cr-Al distance in the vicinity of the defects are detected using transmission electron microscopy. The here observed deformation surrounding the defects was described using density functional theory by comparing the DOS of bulk Cr₂AlC with the DOS of a strained and unstrained Cr₂AlC(0001) surface. From the partial density of states analysis, it can be learned that Cr-C bonds are stronger than Cr-Al bonds in bulk Cr₂AlC. Upon Cr₂AlC(0001) surface formation, both bonds are weakened. While the Cr-C bonds recover their bulk strength as Cr₂AlC(0001) is strained, the Cr-Al bonds experience only a partial recovery, still being weaker than their bulk counterparts. Hence, the strain induced bond strengthening in Cr₂AlC(0001) is larger for Cr d – C p bonds than for Cr d – Al p bonds. The here observed changes in bonding due to the formation of a strained surface are consistent with the experimentally observed elongation of the Cr-Al distance in the vicinity of nm-scale 3D defects in Cr₂AlC thin films.

Phenotype analysis of male transgenic mice overexpressing mutant IGFBP-2 lacking the Cardin-Weintraub sequence motif: Reduced expression of synaptic markers and myelin basic protein in the brain and a lower degree of anxiety-like behaviour

Brain growth and function are regulated by insulin-like growth factors I and II (IGF-I and IGF-II) but also by IGF-binding proteins (IGFBPs), including IGFBP-2. In addition to modulating IGF activities, IGFBP-2 interacts with a number of components of the extracellular matrix and cell membrane via a Cardin-Weintraub sequence or heparin binding domain (HBD1). The nature and the signalling elicited by these interactions are not fully understood. Here, we examined transgenic mice (H1d-hBP2) overexpressing a mutant human IGFBP-2 that lacks a specific heparin binding domain (HBD1) known as the Cardin-Weintraub sequence. H1d-hBP2 transgenic mice have the genetic background of FVB mice and are characterized by severe deficits in brain growth throughout their lifetime (p<0.05). In tissue lysates from brain hemispheres of 12-21day old male mice, protein levels of the GTPase dynamin-I were significantly reduced (p<0.01). Weight reductions were also found in distinct brain regions in two different age groups (12 and 80weeks). In the younger group, impaired weights were observed in the hippocampus (-34%; p<0.001), cerebellum (-25%; p<0.0001), olfactory bulb (-31%; p<0.05) and prefrontal cortex (-29%; p<0.05). At an age of 12weeks expression of myelin basic protein was reduced (p<0.01) in H1d-BP-2 mice in the cerebellum but not in the hippocampus. At 80weeks of age, weight reductions were similarly present in the cerebellum (-28%; p<0.001) and hippocampus (-31; p<0.05). When mice were challenged in the elevated plus maze, aged but not younger H1d-hBP2 mice displayed significantly less anxiety-like behaviour, which was also observed in a second transgenic mouse model overexpressing mouse IGFBP-2 lacking HBD1 (H1d-mBP2). These in vivo studies provide, for the first time, evidence for a specific role of IGFBP-2 in brain functions associated with anxiety and risk behaviour. These activities of IGFBP-2 could be mediated by the Cardin-Weintraub/HBD1 sequence and are altered in mice expressing IGFBP-2 lacking the HBD1.

Hydrophobic superparamagnetic FePt nanoparticles in hydrophilic poly(N-vinylcaprolactam) microgels: a new multifunctional hybrid system

We report the synthesis of a new multifunctional colloidal hybrid system consisting of thermoresponsive amphiphilic biocompatible poly(N-vinylcaprolactam) microgels loaded with hydrophobic superparamagnetic FePt nanoparticles (NPs).

[The Importance of MicroRNA Deregulation in the Molecular Pathogenesis and Histological Transformation of Follicular Lymphoma]

BACKGROUND

Molecular pathogenesis of follicular lymphoma (FL) is characterized by substantial dysregulation of epigenetic regulators. Many cases of FL are associated with the aberrant expression of non-coding regulatory RNAs, namely microRNAs (miRNA). Here we studied changes in miRNA expression and their association with histological transformation of FL to diffuse large B-cell lymphoma (DLBCL).

MATERIAL AND METHODS

To identify changes in miRNA levels during FL transformation we performed a global expression analysis of 377 miRNAs in 16 samples (8 pairs) from FL patients vs. transformed FL (tFL) (TLDA miRNA cards; Thermo Fisher Scientific). The association of miRNA expression with clinical-biological characteristics and target proteins were further analyzed in a cohort of 89 FL patients.

RESULTS

The miRNA expression profiling of paired FL-tFL samples revealed statistically significant changes in the expression of five miRNAs (p < 0.05). Four of them were down-regulated and one was up-regulated in tFL compared to FL. Lower levels of one of these miRNA were also associated with higher proliferation rate of FL cells (Ki-67 > 20%), higher FLIPI score ( 3) and shorter overall survival of FL patients. Furthermore, we found that this miRNA regulates the levels of FOXP1 protein in FL. The patients with high-level FOXP1 expression (> 70% positive cells) had significantly shorter overall survival in comparison to those with low-level FOXP1 expression (< 30% positive cells). Moreover, FOXP1 protein levels were higher in most tFL samples compared to FL before transformation.

CONCLUSION

We found miRNAs associated with the transformation of FL to a more aggressive DLBCL, and described that one of them could serve as a prognostic marker. We found that reduced expression of this tFL-associated miRNA results in increased levels of FOXP1 protein and we assume that the increased activity of FOXP1 proto-oncogene contributes to the histological transformation of FL.Key words: follicular lymphoma - microRNA - histological transformation This work was supported by Czech Ministry of Health registration No. 16-29622A. All rights reserved. The authors declare they have no potential conflicts of interest concerning drugs, products, or services used in the study. The Editorial Board declares that the manuscript met the ICMJE recommendation for biomedical papers.Submitted: 5. 3. 2017Accepted: 26. 3. 2017.

Effects of dynamic diffraction conditions on magnetic parameter determination in a double perovskite Sr2FeMoO6 using electron energy-loss magnetic chiral dichroism

Electron energy-loss magnetic chiral dichroism (EMCD) spectroscopy, which is similar to the well-established X-ray magnetic circular dichroism spectroscopy (XMCD), can determine the quantitative magnetic parameters of materials with high spatial resolution. One of the major obstacles in quantitative analysis using the EMCD technique is the relatively poor signal-to-noise ratio (SNR), compared to XMCD. Here, in the example of a double perovskite Sr₂FeMoO₆, we predicted the optimal dynamical diffraction conditions such as sample thickness, crystallographic orientation and detection aperture position by theoretical simulations. By using the optimized conditions, we showed that the SNR of experimental EMCD spectra can be significantly improved and the error of quantitative magnetic parameter determined by EMCD technique can be remarkably lowered. Our results demonstrate that, with enhanced SNR, the EMCD technique can be a unique tool to understand the structure-property relationship of magnetic materials particularly in the high-density magnetic recording and spintronic devices by quantitatively determining magnetic structure and properties at the nanometer scale.

Homogeneity and variation of donor doping in Verneuil-grown SrTiO3:Nb single crystals

The homogeneity of Verneuil-grown SrTiO3:Nb crystals was investigated. Due to the fast crystal growth process, inhomogeneities in the donor dopant distribution and variation in the dislocation density are expected to occur. In fact, for some crystals optical studies show variations in the density of Ti(3+) states on the microscale and a cluster-like surface conductivity was reported in tip-induced resistive switching studies. However, our investigations by TEM, EDX mapping, and 3D atom probe reveal that the Nb donors are distributed in a statistically random manner, indicating that there is clearly no inhomogeneity on the macro-, micro-, and nanoscale in high quality Verneuil-grown crystals. In consequence, the electronic transport in the bulk of donor-doped crystals is homogeneous and it is not significantly channelled by extended defects such as dislocations which justifies using this material, for example, as electronically conducting substrate for epitaxial oxide film growth.

European LeukemiaNet recommendations for the management and avoidance of adverse events of treatment in chronic myeloid leukaemia

Most reports on chronic myeloid leukaemia (CML) treatment with tyrosine kinase inhibitors (TKIs) focus on efficacy, particularly on molecular response and outcome. In contrast, adverse events (AEs) are often reported as infrequent, minor, tolerable and manageable, but they are increasingly important as therapy is potentially lifelong and multiple TKIs are available. For this reason, the European LeukemiaNet panel for CML management recommendations presents an exhaustive and critical summary of AEs emerging during CML treatment, to assist their understanding, management and prevention. There are five major conclusions. First, the main purpose of CML treatment is the antileukemic effect. Suboptimal management of AEs must not compromise this first objective. Second, most patients will have AEs, usually early, mostly mild to moderate, and which will resolve spontaneously or are easily controlled by simple means. Third, reduction or interruption of treatment must only be done if optimal management of the AE cannot be accomplished in other ways, and frequent monitoring is needed to detect resolution of the AE as early as possible. Fourth, attention must be given to comorbidities and drug interactions, and to new events unrelated to TKIs that are inevitable during such a prolonged treatment. Fifth, some TKI-related AEs have emerged which were not predicted or detected in earlier studies, maybe because of suboptimal attention to or absence from the preclinical data. Overall, imatinib has demonstrated a good long-term safety profile, though recent findings suggest underestimation of symptom severity by physicians. Second and third generation TKIs have shown higher response rates, but have been associated with unexpected problems, some of which could be irreversible. We hope these recommendations will help to minimise adverse events, and we believe that an optimal management of them will be rewarded by better TKI compliance and thus better CML outcomes, together with better quality of life.