Project description:A recurrent chromosomal translocation detected in cannibalistic acute myeloid leukemia leads to the production of a ZMYND11-MBTD1 fusion protein.
- The ZMYND11-MBTD1 fusion protein is stably incorporated into the endogenous NuA4/TIP60 complex
- ZMYND11-MBTD1 leads to mistargeting of NuA4-TIP60 activity to the coding region of ZMYND11-target genes, altering gene expression and transcript isoforms.
- ZMYND11-MBTD1 binds the MYC gene leading to its upregulation, favoring growth and pluripotency while inhibiting differentiation markers.
Project description:Core binding factor (CBF) leukemias, characterized by either inv(16)/t(16;16) or t(8;21), constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, there exists substantial biological and clinical heterogeneity within these cytogenetic groups, which is not fully reflected by the current classification system. To improve the molecular characterization we profiled gene expression in a large series (n=93) of AML patients with CBF leukemia [inv(16) n=55, t(8;21) n=38]. By unsupervised hierarchical clustering we were able to define a subgroup of CBF cases (n=35) characterized by shorter overall survival times (P=0.03). While there was no obvious correlation with fusion gene transcript levels, FLT3 tyrosine kinase domain, KIT, and NRAS mutations, the newly defined inv(16)/t(8;21)-subgroup was associated with elevated white blood cell counts and FLT3 internal tandem duplications (P=0.011 and P=0.026, respectively). Supervised analyses of gene expression suggested alternative cooperating pathways leading to transformation. In the ?favorable? CBF leukemias anti-apoptotic mechanisms and deregulated mTOR-signaling, and in the newly defined ?unfavorable? subgroup aberrant MAPKinase-signaling and chemotherapy-resistance mechanisms might play a role. While the leukemogenic relevance of these signatures remains to be validated, their existence nevertheless supports a prognostically relevant biological basis for the heterogeneity observed in CBF leukemia.
Project description:Acute promyelocytic leukemia (APL) is a subtype of myeloid leukemia characterized by differentiation block at the promyelocyte stage. Besides the presence of chromosomal rearrangement t(15;17) leading to formation of PML-RARA fusion, other genetic alterations have also been implicated in APL. Here, we performed comprehensive mutational analysis of primary and relapse APL to identify somatic alterations which cooperate with PML-RARA in the pathogenesis of APL. We explored the mutational landscape using whole-exome (n=12) and subsequent targeted sequencing of 398 genes in 153 primary and 69 relapse APL. Both primary and relapse APL harbored an average of eight non-silent somatic mutations per exome. We observed recurrent alterations of FLT3, WT1, NRAS and KRAS in the newly diagnosed APL, while mutations in other genes commonly mutated in myeloid leukemia were rarely detected. The molecular signature of APL relapse was characterized by emergence of frequent mutations in PML and RARA genes. Our sequencing data also demonstrates incidence of loss-of-function mutations in previously unidentified genes, ARID1B and ARID1A, both of which encode for key components of the SWI/SNF complex. We show that knockdown of ARID1B in APL cell line, NB4, results in large scale activation of gene expression and reduced in vitro differentiation potential. Studying the effects of silensing ARID1B gene in NB4 cell lines
Project description:This study identifies HOXA9 protein interactome in acute myeloid leukemia cells. Integrated genomic, transcriptomic and proteomic analyses further demonstrated that the HOXA9-SAFB-chromatin complex associates with NuRD and HP1γ to repress the expression of factors associated with differentiation and apoptosis in leukemia maintenance.
Project description:This study identifies HOXA9 protein interactome in acute myeloid leukemia cells. Integrated genomic, transcriptomic and proteomic analyses further demonstrated that the HOXA9-SAFB-chromatin complex associates with NuRD and HP1γ to repress the expression of factors associated with differentiation and apoptosis in leukemia maintenance.
Project description:Core binding factor (CBF) leukemias, characterized by either inv(16)/t(16;16) or t(8;21), constitute acute myeloid leukemia (AML) subgroups with favorable prognosis. However, there exists substantial biological and clinical heterogeneity within these cytogenetic groups, which is not fully reflected by the current classification system. To improve the molecular characterization we profiled gene expression in a large series (n=93) of AML patients with CBF leukemia [inv(16) n=55, t(8;21) n=38]. By unsupervised hierarchical clustering we were able to define a subgroup of CBF cases (n=35) characterized by shorter overall survival times (P=0.03). While there was no obvious correlation with fusion gene transcript levels, FLT3 tyrosine kinase domain, KIT, and NRAS mutations, the newly defined inv(16)/t(8;21)-subgroup was associated with elevated white blood cell counts and FLT3 internal tandem duplications (P=0.011 and P=0.026, respectively). Supervised analyses of gene expression suggested alternative cooperating pathways leading to transformation. In the ?favorable? CBF leukemias anti-apoptotic mechanisms and deregulated mTOR-signaling, and in the newly defined ?unfavorable? subgroup aberrant MAPKinase-signaling and chemotherapy-resistance mechanisms might play a role. While the leukemogenic relevance of these signatures remains to be validated, their existence nevertheless supports a prognostically relevant biological basis for the heterogeneity observed in CBF leukemia. A reference experiement design type is where all samples are compared to a common reference. Using regression correlation
Project description:The myeloid transcription factor CEBPA is recurrently biallelically mutated (i.e., double mutated; CEBPADM) in acute myeloid leukemia (AML) with a combination of hypermorphic N-terminal mutations (CEBPANT), promoting expression of the leukemia-associated p30 isoform, and amorphic C-terminal mutations. CEBPADM AML features recurrent co-occurring mutations including GATA2 lesions, however insights into mechanisms governing this co-mutational spectrum are incomplete. By combining transcriptomic and epigenomic analyses of CEBPA-TET2 co-mutated patients with models thereof, we identify GATA2 as a conserved target of the CEBPA-TET2 mutational axis, providing a rationale for the mutational spectra in CEBPADM AML. Mechanistically, we suggest that elevated CEBPA levels, driven by CEBPANT, mediate recruitment of TET2 to the Gata2 distal hematopoietic enhancer thereby increasing Gata2 expression. Conversely, CEBPADM AML gains a competitive advantage through TET2 loss, by decreasing Gata2 promoter demethylation thereby rebalancing GATA2 levels. Of clinical relevance, demethylating treatment of Cebpa-Tet2 co-mutated AML restores Gata2 levels and prolongs disease latency.
Project description:The myeloid transcription factor CEBPA is recurrently biallelically mutated (i.e., double mutated; CEBPADM) in acute myeloid leukemia (AML) with a combination of hypermorphic N-terminal mutations (CEBPANT), promoting expression of the leukemia-associated p30 isoform, and amorphic C-terminal mutations. CEBPADM AML features recurrent co-occurring mutations including GATA2 lesions, however insights into mechanisms governing this co-mutational spectrum are incomplete. By combining transcriptomic and epigenomic analyses of CEBPA-TET2 co-mutated patients with models thereof, we identify GATA2 as a conserved target of the CEBPA-TET2 mutational axis, providing a rationale for the mutational spectra in CEBPADM AML. Mechanistically, we suggest that elevated CEBPA levels, driven by CEBPANT, mediate recruitment of TET2 to the Gata2 distal hematopoietic enhancer thereby increasing Gata2 expression. Conversely, CEBPADM AML gains a competitive advantage through TET2 loss, by decreasing Gata2 promoter demethylation thereby rebalancing GATA2 levels. Of clinical relevance, demethylating treatment of Cebpa-Tet2 co-mutated AML restores Gata2 levels and prolongs disease latency.