Epigenetic dysregulation in chronic myeloid leukaemia: A myriad of mechanisms and therapeutic options

The onset of global epigenetic changes in chromatin that drive tumor proliferation and heterogeneity is a hallmark of many forms cancer. Identifying the epigenetic mechanisms that govern these changes and developing therapeutic approaches to modulate them, is a well-established avenue pursued in translational cancer medicine. Chronic myeloid leukemia (CML) arises clonally when a hematopoietic stem cell (HSC) acquires the capacity to produce the constitutively active tyrosine kinase BCR-ABL1 fusion protein which drives tumor development. Treatment with tyrosine kinase inhibitors (TKI) that target BCR-ABL1 has been transformative in CML management but it does not lead to cure in the vast majority of patients. Thus novel therapeutic approaches are required and these must target changes to biological pathways that are aberrant in CML − including those that occur when epigenetic mechanisms are altered. These changes may be due to alterations in DNA or histones, their biochemical modifications and requisite ‘writer’ proteins, or to dysregulation of various types of non-coding RNAs that collectively function as modulators of transcriptional control and DNA integrity. Here, we review the evidence for subverted epigenetic mechanisms in CML and how these impact on a diverse set of biological pathways, on disease progression, prognosis and drug resistance. We will also discuss recent progress towards developing epigenetic therapies that show promise to improve CML patient care and may lead to improved cure rates

Dopamine D1, D2 and mu-opioid receptors are co-expressed with adenylyl cyclase 5 and phosphodiesterase 7B mRNAs in striatal rat cells

El pdf es la versión post-print.Intracellular cAMP levels are regulated by cAMP synthesis and degradation rate. Nine isoforms of cAMP-synthesizing enzymes called adenylyl-cyclases (ACs) and eleven phosphodiesterases (PDEs) that degrade cyclic nucleotides have been identified. Both types of enzymes exhibit variations not only in their expression pattern distribution throughout the brain, but also in their regulatory characteristics. Different isoforms of ACs and PDEs may be co-expressed in a single cell, thus a gradient of cAMP intracellular levels is formed, which accounts for the diversity of cell responses. Among these isoforms, AC5 and PDE7B are highly expressed in striatum, where the cAMP pathway is implicated in diverse behavioural functions. Striatal AC5 is involved in drug reinforcing actions and motor activity. Less is known about the role of the PDE7B isoenzyme. We performed a double in situ hybridization analysis of the co-expression patterns of AC5 and PDE7B with μ-opioid-receptor (MOR), D1- and D2-receptor mRNAs to contribute to a better understanding in the regulation of cAMP levels under dopamine or opioidergic pathway activation in striatum. We found co-expression of AC5 and PDE7B mRNAs in caudate-putamen and nucleus accumbens; we also encountered that more than 50% of MOR, D2- and D1-expressing cells contained AC5 and PDE7B mRNAs. The presence of AC5 and PDE7B mRNAs in D1- and D2-containing cells suggests the participation of these enzymes in striatal functions involving dopaminergic pathways. Co-localization of both isoenzyme mRNAs with MOR expressing cells suggests their involvement in opioid reinforcing effects. © 2009 Elsevier B.V. All rights reserved.P. de G. is on sabbatical leave supported by Ministerio de Educación y Ciencia (SAB2005-0106). This research was supported by a grant from Ministerio de Educación y Ciencia (SAF2006-10243). Support from the Generalitat de Catalunya (Grup de Recerca de Qualitat 2005-SGR0758) is also acknowledged.Peer Reviewe

Combined population dynamics and entropy modelling supports patient stratification in chronic myeloid leukemia

Modelling the parameters of multistep carcinogenesis is key for a better understanding of cancer progression, biomarker identification and the design of individualized therapies. Using chronic myeloid leukemia (CML) as a paradigm for hierarchical disease evolution we show that combined population dynamic modelling and CML patient biopsy genomic analysis enables patient stratification at unprecedented resolution. Linking CD34+ similarity as a disease progression marker to patientderived gene expression entropy separated established CML progression stages and uncovered additional heterogeneity within disease stages. Importantly, our patient data informed model enables quantitative approximation of individual patients’ disease history within chronic phase (CP) and significantly separates “early” from “late” CP. Our findings provide a novel rationale for personalized and genome-informed disease progression risk assessment that is independent and complementary to conventional measures of CML disease burden and prognosis

Feasibility of azacitidine added to standard chemotherapy in older patients with acute myeloid leukemia - a randomised SAL pilot study

INTRODUCTION: Older patients with acute myeloid leukemia (AML) experience short survival despite intensive chemotherapy. Azacitidine has promising activity in patients with low proliferating AML. The aim of this dose-finding part of this trial was to evaluate feasibility and safety of azacitidine combined with a cytarabine- and daunorubicin-based chemotherapy in older patients with AML. TRIAL DESIGN: Prospective, randomised, open, phase II trial with parallel group design and fixed sample size. PATIENTS AND METHODS: Patients aged 61 years or older, with untreated acute myeloid leukemia with a leukocyte count of <20,000/µl at the time of study entry and adequate organ function were eligible. Patients were randomised to receive azacitidine either 37.5 (dose level 1) or 75 mg/sqm (dose level 2) for five days before each cycle of induction (7+3 cytarabine plus daunorubicine) and consolidation (intermediate-dose cytarabine) therapy. Dose-limiting toxicity was the primary endpoint. RESULTS: Six patients each were randomised into each dose level and evaluable for analysis. No dose-limiting toxicity occurred in either dose level. Nine serious adverse events occurred in five patients (three in the 37.5 mg, two in the 75 mg arm) with two fatal outcomes. Two patients at the 37.5 mg/sqm dose level and four patients at the 75 mg/sqm level achieved a complete remission after induction therapy. Median overall survival was 266 days and median event-free survival 215 days after a median follow up of 616 days. CONCLUSIONS: The combination of azacitidine 75 mg/sqm with standard induction therapy is feasible in older patients with AML and was selected as an investigational arm in the randomised controlled part of this phase-II study, which is currently halted due to an increased cardiac toxicity observed in the experimental arm

Construction and Application of an Inducible System for Homogenous Expression Levels in Bulk Cell Lines

Stringently controlled conditional expressing systems are crucial for the functional characterization of genes. Currently, screening of multiple clones to identify the tightly controlled ones is necessary but time-consuming. Here, we describe a system fusing Tet (tetracycline)-inducible elements, BAC (bacterial artificial chromosome) and Gateway technology together to allow tight control of gene expression in BAC-transfected eukaryotic bulk cell cultures. Recombinase cloning into the shuttle vector and the BAC facilitates vector construction. An EGFP (enhanced green fluorescent protein) allows FACS (fluorescence activated cell sorting) and the BAC technology ensures tight control of gene expression that is independent of the integrating site. In the current first application, our gene of interest encodes a β-catenin-ERα fusion protein. Tested by luciferase assay and western blotting, in HTB56 lung cancer cells the final BAC E11-IGR-β-catenin-ERα vector demonstrated sensitive inducibility by Tet or Dox (doxycycline) in a dose-dependent manner with low background, and the EGFP was an effective selection marker by FACS in bulk culture HTB56 and myeloblastic 32D cells. This is a highly efficient tool for the rapid generation of stringently controlled Tet-inducible systems in cell lines

Repairing Family Law

Scholars in the burgeoning field of law and emotion have paid surprisingly little attention to family law. This gap is unfortunate because law and emotion has the potential to bring great insights to family law. This Article begins to fill this void, and inaugurate a larger debate about the central role of emotion in family law, by exploring the intriguing and significant consequences for the regulation of families that flow from a theory of intimacy first articulated by psychoanalytic theorist Melanie Klein. According to Klein, individuals love others, inevitably transgress against those they love out of hate and aggression, feel guilt about the transgression, and then seek to repair the damage. This Article argues that the legal process embodied in the substance, procedure, and practice of traditional family law is at odds with the human process of love, hate, guilt, and reparation. In contexts as far ranging as divorce, child welfare, and adoption, family law is predicated on a binary model of love and hate, with no accounting for guilt and the drive to reparation. This Love-Hate Model actively thwarts the cycle of intimacy, greatly diminishing the opportunity for repair in familial relationships. In short, reparation as a normative goal receives far too little attention in family law. Although several important reforms have begun to move family law away from the Love-Hate Model, these reforms are undertheorized and incomplete and sometimes actively challenged. An overarching theory is needed both to undergird current reforms and to encourage others, thus moving family law more fully in a reparative direction. To replace the prevailing Love-Hate Model, this Article proposes a Reparative Model of family law that would recognize the full cycle of emotions and facilitate the reparative drive. A Reparative Model would modify the substance of family law to recognize the ongoing relationships that often persist even after legal relationships are altered. It would reform the process of family law by de-emphasizing adversarial decisionmaking. And it would change the practice of family law by reconceiving the role of the family law attorney. Ultimately, the Reparative Model yields new perspectives on a range of theoretical and practical problems in contemporary family law, providing a framework for the law to account for the full, and complex, emotional reality of familial relationships

Rights Myopia in Child Welfare

For decades, legal scholars have debated the proper balance of parents\u27 rights and children\u27s rights in the child welfare system. This Article argues that the debate mistakenly privileges rights. Neither parents\u27 rights nor children\u27s rights serve families well because, as implemented, a solely rights-based model of child welfare does not protect the interests of parents or children. Additionally, even if well-implemented, the model still would not serve parents or children because it obscures the important role of poverty in child abuse and neglect and fosters conflict rather than collaboration between the state and families. In lieu of a solely rights-based model, this Article proposes a problem-solving model for child welfare and explores one embodiment of such a model, family group conferencing. This Article concludes that a problem-solving model holds significant potential to address many of the profound theoretical and practical shortcomings of the current child welfare system

Of autoregressive continuous time model parameters estimation

This article revisits a sequential approach to the estimation of the parameter in a first-order autoregressive model (AR(1)) with continuous time. There is provided a numerical study to get a results of sequential estimations of the parameter in first-order autoregressive model with continuous time and is computed a stopping rule and the optimal time of observations. Also there is provided a comparing analysis of estimation results with using the sequential approach both the optimal time of observations

The SCLtTAxBCR-ABL transgenic mouse model closely reflects the differential effects of dasatinib on normal and malignant hematopoiesis in chronic phase-CML patients

The second generation tyrosine kinase inhibitor (TKI) dasatinib is a clinically approved drug for chronic myeloid leukemia (CML) as well as Ph+ acute lymphoblastic leukemia. In addition to its antileukemic effects, dasatinib was shown to impact on normal hematopoiesis and cells of the immune system. Due to the fact that the murine in vivo studies so far have not been performed in a chronic-phase CML model under steady-state conditions, our aim was to study the hematopoietic effects of dasatinib (20 mg/kg p.o.) in BCR-ABL expressing SCLtTAxBCR-ABL double transgenic (dtg) mice. Dasatinib robustly antagonized the CML phenotype in vivo in our transgenic mouse model, and this effect included both mature and immature cell populations. However, similar to patients with CML, the fraction of Lin(neg)Sca-1(+)KIT(+)CD48(neg)CD150(+) hematopoietic stem cells was not reduced by dasatinib treatment, suggesting that these cells are not oncogene-addicted. Moreover, we observed differential effects of dasatinib in these animals as compared to wild-type (wt) animals: while granulocytes were significantly reduced in dtg animals, they were increased in wt mice. And Ter119(+) erythrocytic and B220(+) B cells were increased in dtg mice but decreased in wt mice. Finally, while dasatinib induced a shift from CD49b/NK1.1 positive NK cells from the bone marrow to the spleen in wt animals, there was no change in dtg mice. In conclusion, the present mouse model provides a useful tool to study mechanisms of TKI resistance and dasatinib-associated beneficial effects and adverse events.Peer reviewe

A Limited Role for the Cell Cycle Regulator Cyclin A1 in Murine Leukemogenesis

The quest for novel therapeutic targets in acute myeloid leukemia (AML) is still ongoing. One of such targets, cyclin A1, was shown to be overexpressed in AML including AML stem cells. However, the function of cyclin A1 in AML is largely unknown, and the data on its impact on patients´ survival remain controversial. Therefore, we developed a transgenic mouse model of stem cell-directed inducible cyclin A1 overexpression and crossed these mice with PML-RARα-knockin mice, which develop an AML M3-like phenotype. To observe the effects of cyclin A1 loss-of-function, we also crossed PML-RARα-knockin mice to cyclin A1-knockout mice. Neither overexpression nor loss of cyclin A1 significantly altered leukemogenesis in PML-RARα-knockin mice. These findings imply that upregulation of cyclin A1 is not essential for leukemogenesis. Our data suggest that cyclin A1 does not represent a suitable target for AML therapy