The role of MYC and PP2A in the initiation and progression of myeloid leukemias

The MYC transcription factor is one of the best characterized PP2A substrates. Deregulation of the MYC oncogene, along with inactivation of PP2A, are two frequent events in cancer. Both proteins are essential regulators of cell proliferation, apoptosis, and differentiation, and they, directly and indirectly, regulate each other's activity. Studies in cancer suggest that targeting the MYC/PP2A network is an achievable strategy for the clinic. Here, we focus on and discuss the role of MYC and PP2A in myeloid leukemias

A new regulatory mechanism of protein phosphatase 2A activity via SET in acute myeloid leukemia

Acute myeloid leukemia (AML) is an aggressive hematologic malignancy. Although novel emerging drugs are available, the overall prognosis remains poor and new therapeutic approaches are required. PP2A phosphatase is a key regulator of cell homeostasis and is recurrently inactivated in AML. The anticancer activity of several PP2A-activating drugs (e.g., FTY720) depends on their interaction with the SET oncoprotein, an endogenous PP2A inhibitor that is overexpressed in 30% of AML cases. Elucidation of SET regulatory mechanisms may therefore provide novel targeted therapies for SET-overexpressing AMLs. Here, we show that upregulation of protein kinase p38 beta is a common event in AML. We provide evidence that p38 beta potentiates SET-mediated PP2A inactivation by two mechanisms: facilitating SET cytoplasmic translocation through CK2 phosphorylation, and directly binding to and stabilizing the SET protein. We demonstrate the importance of this new regulatory mechanism in primary AML cells from patients and in zebrafish xenograft models. Accordingly, combination of the CK2 inhibitor CX-4945, which retains SET in the nucleus, and FTY720, which disrupts the SET-PP2A binding in the cytoplasm, significantly reduces the viability and migration of AML cells. In conclusion, we show that the p38 beta/CK2/SET axis represents a new potential therapeutic pathway in AML patients with SET-dependent PP2A inactivation

One-step rapid tracking and isolation of senescent cells in cellular systems, tissues, or animal models via GLF16

Identification and isolation of senescent cells is challenging, rendering their detailed analysis an unmet need. We describe a precise one-step protocol to fluorescently label senescent cells, for flow cytometry and fluorescence microscopy, implementing a fluorophore-conjugated Sudan Black-B analog, GLF16. Also, a micelle-based approach allows identification of senescent cells in vivo and in vitro, enabling live-cell sorting for downstream analyses and live in vivo tracking. Our protocols are applicable to cellular systems, tissues, or animal models where senescence is present. For complete details on the use and execution of this protocol, please refer to Magkouta et al.</p

Expression of DISC1-Interactome Members Correlates with Cognitive Phenotypes Related to Schizophrenia

Cognitive dysfunction is central to the schizophrenia phenotype. Genetic and functional studies have implicated Disrupted-in-Schizophrenia 1 (DISC1), a leading candidate gene for schizophrenia and related psychiatric conditions, in cognitive function. Altered expression of DISC1 and DISC1-interactors has been identified in schizophrenia. Dysregulated expression of DISC1-interactome genes might, therefore, contribute to schizophrenia susceptibility via disruption of molecular systems required for normal cognitive function. Here, the blood RNA expression levels of DISC1 and DISC1-interacting proteins were measured in 63 control subjects. Cognitive function was assessed using neuropsychiatric tests and functional magnetic resonance imaging was used to assess the activity of prefrontal cortical regions during the N-back working memory task, which is abnormal in schizophrenia. Pairwise correlations between gene expression levels and the relationship between gene expression levels and cognitive function and N-back-elicited brain activity were assessed. Finally, the expression levels of DISC1, AKAP9, FEZ1, NDEL1 and PCM1 were compared between 63 controls and 69 schizophrenic subjects. We found that DISC1-interactome genes showed correlated expression in the blood of healthy individuals. The expression levels of several interactome members were correlated with cognitive performance and N-back-elicited activity in the prefrontal cortex. In addition, DISC1 and NDEL1 showed decreased expression in schizophrenic subjects compared to healthy controls. Our findings highlight the importance of the coordinated expression of DISC1-interactome genes for normal cognitive function and suggest that dysregulated DISC1 and NDEL1 expression might, in part, contribute to susceptibility for schizophrenia via disruption of prefrontal cortex-dependent cognitive functions

The Role of MYC and PP2A in the Initiation and Progression of Myeloid Leukemias

The MYC transcription factor is one of the best characterized PP2A substrates. Deregulation of the MYC oncogene, along with inactivation of PP2A, are two frequent events in cancer. Both proteins are essential regulators of cell proliferation, apoptosis, and differentiation, and they, directly and indirectly, regulate each other&rsquo;s activity. Studies in cancer suggest that targeting the MYC/PP2A network is an achievable strategy for the clinic. Here, we focus on and discuss the role of MYC and PP2A in myeloid leukemias

Importance of genetics in acute myeloid leukemia

Acute myeloid leukemia (AML) comprises a biologically and clinically heterogeneous group of aggressive disorders that occur as a consequence of a wide variety of genetic and epigenetic abnormalities in hematopoietic progenitors. Despite significant advances in the understanding of the biology of AML, most patients will die from relapsed disease. Whole-genome studies have identified novel recurrent gene mutations with prognostic impact in AML; furthermore, it is likely that in the near future genome-wide sequencing will become a routine for newly diagnosed patients with AML. Therefore, future clinical trials should aim to identify genetically defined high-risk patients, and further research is necessary to identify effective agents and develop new individualized therapeutic strategies for the treatment of this deadly disease.La leucemia mieloide aguda (LMA) es una enfermedad clínica y molecularmente heterogénea, que surge como consecuencia de alteraciones genéticas y epigenéticas adquiridas en células progenitoras hematopoyéticas. A pesar de los avances realizados en el conocimiento de la biología de esta enfermedad, la supervivencia global de los pacientes sigue siendo muy baja debido principalmente a la alta tasa de recaídas. Los estudios de secuenciación masiva han permitido la identificación de nuevas mutaciones recurrentes y con impacto pronóstico en LMA; además, parece probable que en poco tiempo la secuenciación de todo el genoma sea una prueba diagnóstica de rutina, lo que permitirá el diagnóstico molecular de los pacientes. Por tanto, es necesario el desarrollo de dianas moleculares que abran nuevas perspectivas terapéuticas y permitan el tratamiento individualizado de los pacientes con esta enfermedad tan agresiva

Importance of genetics in acute myeloid leukemia

Acute myeloid leukemia (AML) comprises a biologically and clinically heterogeneous group of aggressive disorders that occur as a consequence of a wide variety of genetic and epigenetic abnormalities in hematopoietic progenitors. Despite significant advances in the understanding of the biology of AML, most patients will die from relapsed disease. Whole-genome studies have identified novel recurrent gene mutations with prognostic impact in AML; furthermore, it is likely that in the near future genome-wide sequencing will become a routine for newly diagnosed patients with AML. Therefore, future clinical trials should aim to identify genetically defined high-risk patients, and further research is necessary to identify effective agents and develop new individualized therapeutic strategies for the treatment of this deadly disease.La leucemia mieloide aguda (LMA) es una enfermedad clínica y molecularmente heterogénea, que surge como consecuencia de alteraciones genéticas y epigenéticas adquiridas en células progenitoras hematopoyéticas. A pesar de los avances realizados en el conocimiento de la biología de esta enfermedad, la supervivencia global de los pacientes sigue siendo muy baja debido principalmente a la alta tasa de recaídas. Los estudios de secuenciación masiva han permitido la identificación de nuevas mutaciones recurrentes y con impacto pronóstico en LMA; además, parece probable que en poco tiempo la secuenciación de todo el genoma sea una prueba diagnóstica de rutina, lo que permitirá el diagnóstico molecular de los pacientes. Por tanto, es necesario el desarrollo de dianas moleculares que abran nuevas perspectivas terapéuticas y permitan el tratamiento individualizado de los pacientes con esta enfermedad tan agresiva

The role of MYC and PP2A in the initiation and progression of myeloid leukemias

The MYC transcription factor is one of the best characterized PP2A substrates. Deregulation of the MYC oncogene, along with inactivation of PP2A, are two frequent events in cancer. Both proteins are essential regulators of cell proliferation, apoptosis, and differentiation, and they, directly and indirectly, regulate each other's activity. Studies in cancer suggest that targeting the MYC/PP2A network is an achievable strategy for the clinic. Here, we focus on and discuss the role of MYC and PP2A in myeloid leukemias

New insights on the transcriptional regulation of CD69 gene through a potent enhancer located in the conserved non-coding sequence 2.

The CD69 type II C-type lectin is one of the earliest indicators of leukocyte activation acting in lymphocyte migration and cytokine secretion. CD69 expression in hematopoietic lineage undergoes rapid changes depending on the cell-lineage, the activation state or the localization of the cell where it is expressed, suggesting a complex and tightly controlled regulation. Here we provide new insights on the transcriptional regulation of CD69 gene in mammal species. Through in silico studies, we analyzed several regulatory features of the 4 upstream conserved non-coding sequences (CNS 1-4) previously described, confirming a major function of CNS2 in the transcriptional regulation of CD69. In addition, multiple transcription binding sites are identified in the CNS2 region by DNA cross-species conservation analysis. By functional approaches we defined a core region of 226bp located within CNS2 as the main enhancer element of CD69 transcription in the hematopoietic cells analyzed. By chromatin immunoprecipitation, binding of RUNX1 to the core-CNS2 was shown in a T cell line. In addition, we found an activating but not essential role of RUNX1 in CD69 gene transcription by site-directed mutagenesis and RNA silencing, probably through the interaction with this potent enhancer specifically in the hematopoietic lineage. In summary, in this study we contribute with new evidences to the landscape of the transcriptional regulation of the CD69 gene.We thank Dr. Elisenda Alari-Pahissa and Dr. Begoña Galocha for their critical review of the manuscript. This work was supported by the Spanish Ministry of Economics (SAF2010-15649) and the Carlos III National Health Institute (ISCIII)-RTICC (RD12/0036/0063). T. Laguna and L. Notario were supported by Predoctoral Fellowships from the Spanish Ministry of Education and Science.S