SirT7 auto-ADP-ribosylation regulates glucose starvation response through mH2A1Science Advances 24 Jul 2020, 6 .
Sirtuins are key players of metabolic stress response. Originally described as deacetylases, some sirtuins also exhibit poorly understood mono–adenosine 5′-diphosphate (ADP)–ribosyltransferase (mADPRT) activity. We report that the deacetylase SirT7 is a dual sirtuin, as it also features auto-mADPRT activity. SirT7 mADPRT occurs at a previously undefined active site, and its abrogation alters SirT7 chromatin distribution. We identify an epigenetic pathway by which ADP-ribosyl-SirT7 is recognized by the ADP-ribose reader mH2A1.1 under glucose starvation, inducing SirT7 relocalization to intergenic regions. SirT7 promotes mH2A1 enrichment in a subset of nearby genes, many of them involved in second messenger signaling, resulting in their specific up- or down-regulation. The expression profile of these genes under calorie restriction is consistently abrogated in SirT7-deficient mice, resulting in impaired activation of autophagy. Our work provides a novel perspective on sirtuin duality and suggests a role for SirT7/mH2A1.1 axis in glucose homeostasis and aging.
The Contribution of Epigenetics to Cancer ImmunotherapyTrends in Immunology 1 Jul 2020, .
Effective anticancer immunotherapy treatments constitute a qualitative leap in cancer management. Nonetheless, not all patients benefit from such therapies because they fail to achieve complete responses, suffer frequent relapses, or develop potentially life-threatening toxicities. Epigenomic signatures in immune and cancer cells appear to be accurate and promising predictors of patient outcomes with immunotherapy. In addition, combined treatments with epigenetic drugs can exploit the dynamic nature of epigenetic changes to potentially modulate responses to immunotherapy. Candidate epigenetic biomarkers may provide a rationale for patient stratification and precision medicine, thus maximizing the chances of treatment success while minimizing unwanted effects. We present a comprehensive up-to-date view of potential epigenetic biomarkers in immunotherapy and discuss their advantages over other indicators.More information
Epitranscriptomics in Hematopoiesis and Hematologic Malignancies.Blood Cancer Discovery 22 Jun 2020, .
Since the 1960s, a large number of chemical modifications have been identified in RNA molecules, establishing the RNA epigenetics field named “epitranscriptomics.” These chemical marks participate in several RNA metabolic processes; however, the biological relevance of many of these modifications and the many enzymes involved in their function is not completely understood. Emerging knowledge of the epitranscriptome (pseudouridine, N6-methyladenosine, and A-to-I editing) in hematopoiesis and hematologic malignancies reveals the requirement of these modifications in normal development and their alteration in disorders, leading to the development of new molecules and strategies to target the epitranscriptome as a novel therapeutic approach. RNA modifications are required for the correct development of hematopoietic cells, and their alteration can promote the development of malignancies or the transition from a low-grade to an aggressive disease. While we are expanding our understanding of the epitranscriptome of normal and malignant hematopoiesis, the number of potential new therapeutic interventions is rising.
The DNA methylation landscape of hematological malignancies: an update.Mol Oncol 11 Jun 2020, . Epub 11 Jun 2020
The rapid advances in high-throughput sequencing technologies have made it more evident that epigenetic modifications orchestrate a plethora of complex biological processes. During the last decade, we have gained significant knowledge about a wide range of epigenetic changes that crucially contribute to some of the most aggressive forms of leukemia, lymphoma and myelodysplastic syndromes. DNA methylation is a key epigenetic player in the abnormal initiation, development and progression of these malignancies, often acting in synergy with other epigenetic alterations. It also contributes to the acquisition of drug resistance. In this review, we summarize the role of DNA methylation in hematological malignancies described in the current literature. We discuss in detail the dual role of DNA methylation in normal and aberrant hematopoiesis, as well as the involvement of this type of epigenetic change in other aspects of the disease. Finally, we present a comprehensive overview of the main clinical implications, including a discussion of the therapeutic strategies that regulate or reverse aberrant DNA methylation patterns in hematological malignancies, including their combination with (chemo-) immunotherapy.More information