Project description:Oncogenic transcription factors such as the leukaemic fusion protein RUNX1/ETO constitute cancer-specific but highly challenging therapeutic targets, whose functions depend on pharmacologically tractable downstream pathways. Here we interrogated the transcriptional network of RUNX1/ETO in an in vitro/in vivo RNAi screen and identified Cyclin D2 (CCND2) as a crucial transmitter of RUNX1/ETO-driven leukemic propagation. RUNX1/ETO drives CCND2 expression by binding to a regulatory element upstream of the CCND2 promoter. Both knockdown of CCND2 and treatment with the CDK4/6 inhibitor palbociclib inhibited leukemic expansion patient-derived AML cells and impaired engraftment of immunodeficient murine hosts. Our data demonstrate that RUNX1/ETO drives leukaemia by directly promoting cell cycle progression and establish inhibition of G1 CCND-CDK complexes as a promising therapeutic strategy for RUNX1/ETO-driven AML.
Project description:Oncogenic transcription factors such as the leukaemic fusion protein RUNX1/ETO constitute cancer-specific but highly challenging therapeutic targets, whose functions depend on pharmacologically tractable downstream pathways. Here we interrogated the transcriptional network of RUNX1/ETO in an in vitro/in vivo RNAi screen and identified Cyclin D2 (CCND2) as a crucial transmitter of RUNX1/ETO-driven leukemic propagation. RUNX1/ETO drives CCND2 expression by binding to a regulatory element upstream of the CCND2 promoter. Both knockdown of CCND2 and treatment with the CDK4/6 inhibitor palbociclib inhibited leukemic expansion patient-derived AML cells and impaired engraftment of immunodeficient murine hosts. Our data demonstrate that RUNX1/ETO drives leukaemia by directly promoting cell cycle progression and establish inhibition of G1 CCND-CDK complexes as a promising therapeutic strategy for RUNX1/ETO-driven AML.
Project description:Human histone deacetylase 3 (HDAC3) plays an important role in gene transcription in diseased human cells, such as leukemia. The t(8;21) chromosomal translocation is one of the most commonly observed genetic abnormalities associated with acute myeloid leukemia. This translocation generates the AML1-ETO fusion protein between the wild-type RUNX1 transcription factor and wild-type ETO transcriptional corepressor. To better understand the role of HDAC3 in t(8;21) leukemogenesis, the human HDAC3-containing complexes were isolated from stably-transfected HeLa cells by using anti-FLAG immunoprecipitation. The resulting complexes were resolved in SDS-PAGE. The components of the complexes were identified using LC-MS/MS. We report here that the human RUNX1 transcription is a component of the HDAC3 complexes. We demonstrate that HDAC3 and RUNX1 collaboratively repress AML1-ETO-mediated transcription. These results reveal new insight into how AML1-ETO, RUNX1, and HDAC3 crosstalk to deregulate gene transcription in t(8;21) leukemia cells.
Project description:Oncogenic transcription factors such as the leukemic fusion protein RUNX1/ETO, which drives t(8;21) acute myeloid leukemia (AML), constitute cancer-specific but highly challenging therapeutic targets. We used epigenomic profiling data for an RNAi screen to interrogate the transcriptional network maintaining t(8;21) AML. This strategy identified Cyclin D2 (CCND2) as a crucial transmitter of RUNX1/ETO-driven leukemic propagation. RUNX1/ETO cooperates with AP-1 to drive CCND2 expression. Knockdown or pharmacological inhibition of CCND2 by an approved drug significantly impairs leukemic expansion of patient-derived AML cells and engraftment in immunodeficient murine hosts. Our data demonstrate that RUNX1/ETO maintains leukemia by promoting cell cycle progression and identifies G1 CCND-CDK complexes as promising therapeutic targets for treatment of RUNX1/ETO-driven AML.
Project description:The t(8;21) translocation fuses the DNA binding domain of the hematopoietic master regulator RUNX1 to the ETO protein. The resultant RUNX1/ETO fusion protein is a leukemia-initiating transcription factor that interferes with RUNX1 function. The result of this interference is a block in differentiation and, finally, the development of acute myeloid leukemia (AML). To obtain insights into RUNX1/ETO-dependant alterations of the epigenetic landscape we measured genome-wide RUNX1- and RUNX1/ETO bound regions in t(8;21) cells and assessed to what extent the effects of RUNX1/ETO on the epigenome depend on its continued expression in established leukemic cells. To this end we determined dynamic alterations of histone acetylation, RNA Polymerase II binding and RUNX1 occupancy in the presence or absence of RUNX1/ETO using a knockdown approach. Combined global assessments of chromatin accessibility and kinetic gene expression data show that RUNX1/ETO controls the expression of important regulators of hematopoietic differentiation and self-renewal. We show that selective removal of RUNX1/ETO leads to a widespread reversal of epigenetic reprogramming and a genome-wide re-distribution of RUNX1 binding, resulting in the inhibition of leukemic proliferation and self-renewal and the induction of differentiation. This demonstrates that RUNX1/ETO represents a pivotal therapeutic target in AML. Total RNA were obtained using 8 samples over a time course of 10 days or using two samples two days after siRNA electroporation (mismatch control siRNA and RUNX1/ETO knock-down)
Project description:The t(8;21) translocation fuses the DNA binding domain of the hematopoietic master regulator RUNX1 to the ETO protein. The resultant RUNX1/ETO fusion protein is a leukemia-initiating transcription factor that interferes with RUNX1 function. The result of this interference is a block in differentiation and, finally, the development of acute myeloid leukemia (AML). To obtain insights into RUNX1/ETO-dependant alterations of the epigenetic landscape we measured genome-wide RUNX1- and RUNX1/ETO bound regions in t(8;21) cells and assessed to what extent the effects of RUNX1/ETO on the epigenome depend on its continued expression in established leukemic cells. To this end we determined dynamic alterations of histone acetylation, RNA Polymerase II binding and RUNX1 occupancy in the presence or absence of RUNX1/ETO using a knockdown approach. Combined global assessments of chromatin accessibility and kinetic gene expression data show that RUNX1/ETO controls the expression of important regulators of hematopoietic differentiation and self-renewal. We show that selective removal of RUNX1/ETO leads to a widespread reversal of epigenetic reprogramming and a genome-wide re-distribution of RUNX1 binding, resulting in the inhibition of leukemic proliferation and self-renewal and the induction of differentiation. This demonstrates that RUNX1/ETO represents a pivotal therapeutic target in AML. This SuperSeries is composed of the SubSeries listed below.
Project description:The t(8;21) translocation fuses the DNA binding domain of the hematopoietic master regulator RUNX1 to the ETO protein. The resultant RUNX1/ETO fusion protein is a leukemia-initiating transcription factor that interferes with RUNX1 function. The result of this interference is a block in differentiation and, finally, the development of acute myeloid leukemia (AML). To obtain insights into RUNX1/ETO-dependant alterations of the epigenetic landscape we measured genome-wide RUNX1- and RUNX1/ETO bound regions in t(8;21) cells and assessed to what extent the effects of RUNX1/ETO on the epigenome depend on its continued expression in established leukemic cells. To this end we determined dynamic alterations of histone acetylation, RNA Polymerase II binding and RUNX1 occupancy in the presence or absence of RUNX1/ETO using a knockdown approach. Combined global assessments of chromatin accessibility and kinetic gene expression data show that RUNX1/ETO controls the expression of important regulators of hematopoietic differentiation and self-renewal. We show that selective removal of RUNX1/ETO leads to a widespread reversal of epigenetic reprogramming and a genome-wide re-distribution of RUNX1 binding, resulting in the inhibition of leukemic proliferation and self-renewal and the induction of differentiation. This demonstrates that RUNX1/ETO represents a pivotal therapeutic target in AML.
Project description:The t(8;21) translocation fuses the DNA binding domain of the hematopoietic master regulator RUNX1 to the ETO protein. The resultant RUNX1/ETO fusion protein is a leukemia-initiating transcription factor that interferes with RUNX1 function. The result of this interference is a block in differentiation and, finally, the development of acute myeloid leukemia (AML). To obtain insights into RUNX1/ETO-dependant alterations of the epigenetic landscape we measured genome-wide RUNX1- and RUNX1/ETO bound regions in t(8;21) cells and assessed to what extent the effects of RUNX1/ETO on the epigenome depend on its continued expression in established leukemic cells. To this end we determined dynamic alterations of histone acetylation, RNA Polymerase II binding and RUNX1 occupancy in the presence or absence of RUNX1/ETO using a knockdown approach. Combined global assessments of chromatin accessibility and kinetic gene expression data show that RUNX1/ETO controls the expression of important regulators of hematopoietic differentiation and self-renewal. We show that selective removal of RUNX1/ETO leads to a widespread reversal of epigenetic reprogramming and a genome-wide re-distribution of RUNX1 binding, resulting in the inhibition of leukemic proliferation and self-renewal and the induction of differentiation. This demonstrates that RUNX1/ETO represents a pivotal therapeutic target in AML.